British Business Bank anchors Longwall's £100m deeptech fund: What it means for UK deep tech founders

The British Business Bank has committed to anchoring a new £100 million fund managed by Longwall Capital, signalling a major institutional shift in how the UK backs deep technology ventures. For founders building in hard tech, climate, semiconductors, biotech, and other complex engineering domains, this move represents both validation of the sector and a concrete funding pathway that was previously fragmented across scattered sources.

The announcement reflects a broader realisation among UK policy makers and institutional investors that deep tech—technologies that require years of R&D, complex manufacturing, and regulatory navigation—cannot compete for venture capital against faster-scaling software plays. Without dedicated capital pools, Britain risks watching its most ambitious inventors and engineers either relocate abroad or shelve promising ventures.

This article breaks down what the Longwall fund means for the UK deep tech ecosystem, how it works in practice, and what operators need to know about accessing this capital.

What is the Longwall Fund and why does the British Business Bank backing matter?

Longwall Capital is an independent venture capital firm focused specifically on deep technology companies. The firm was founded to address a glaring gap in the UK venture landscape: most traditional VC firms operate on 7–10 year fund cycles and require companies to hit revenue or user growth milestones within 18–36 months. Deep tech doesn't work that way. A hardware startup developing carbon capture technology, a biotech firm running clinical trials, or a semiconductor design house might need 5–7 years before reaching meaningful commercial traction.

By anchoring the £100 million fund, the British Business Bank—the government-backed institution tasked with improving access to growth finance for UK businesses—has essentially co-signed the thesis that deep tech deserves patient, specialist capital. The Bank's backing carries multiple implications:

• Credibility and follow-on funding: When the state-backed institution backs a fund, other institutional investors—pension funds, insurance companies, family offices—follow. Longwall can now credibly recruit additional limited partners (LPs) because the public sector has already done due diligence and risk assessment.
• Longer investment horizons: The British Business Bank's capital comes without the pressure to generate outsized returns in a compressed timeframe. This allows Longwall to hold positions longer and support portfolio companies through multiple product cycles.
• Policy alignment: The move signals that industrial strategy is moving toward supporting innovation in sectors critical to UK competitiveness: green tech, life sciences, advanced manufacturing, and semiconductors.
• Geographic reach: The Bank's existing relationships with regional development bodies and local economic partnerships mean deep tech founders outside London have a clearer route to institutional capital.

In practical terms, this is a £100 million fund deployed over roughly 7–10 years, split across 15–25 companies, with cheques typically ranging from £3–10 million per company. That's meaningful capital for a founder building a prototyping facility or running extended clinical trials, but founders should expect rigorous due diligence and a patient, value-add investment model rather than the rapid-scaling playbook common in software venture capital.

The UK deep tech funding landscape: Why this fund fills a critical gap

To understand why the British Business Bank anchoring Longwall matters, it's worth sketching the funding journey a UK deep tech founder has faced historically.

A typical UK deep tech founder starts with SEIS and EIS tax relief schemes, which allow angel investors and early-stage employees to claim 50% income tax relief on investments up to £100,000 and £1 million respectively. This is excellent for raising the first £500,000–£2 million from high-net-worth individuals and friends-and-family rounds. However, the next step—raising Series A capital of £5–15 million—becomes difficult fast.

Traditional venture capital firms in the UK operate across Midtown London, Cambridge, and Edinburgh. But their thesis is fundamentally software-first. They back companies that can iterate rapidly, reach product-market fit within 18 months, and scale to £10+ million ARR within four years. Founders pitching a battery technology company, a novel diagnostic platform, or an aerospace component manufacturer find themselves explaining why their 5-year R&D timeline isn't a flaw—it's the feature. Many VCs simply pass because the model doesn't fit.

What emerges is a funding valley. Founders with £2–5 million invested might look for follow-on Series A capital and find very few options. Some tap corporate venture arms of large industrials or chemical companies. Others bootstrap using grants from Innovate UK, which offers non-dilutive funding for R&D-heavy projects, or raise via the Start Up Loans scheme (though this is better suited to lower-risk ventures). A minority relocate to the US, where Horizon Ventures, Lowercarbon Capital, and others specialise in 10+ year investment horizons.

Longwall's £100 million fund, anchored by the British Business Bank, is explicitly designed to bridge this gap. It sits between angel/seed funding and later-stage institutional rounds, with capital deployment timelines and return expectations aligned to hardware and biotech realities.

Sector focus: Who benefits from the Longwall fund?

The Longwall fund is open to UK-registered deep tech companies across a broad range of sectors. The firm's investment thesis typically focuses on companies addressing material problems using novel science or engineering. This includes:

• Climate and energy: Carbon capture, fusion energy, next-generation batteries, green hydrogen, and industrial decarbonisation technologies.
• Life sciences and biotech: Novel therapeutics, diagnostics, medical devices, and synthetic biology platforms.
• Semiconductors and advanced electronics: Chip design, semiconductor manufacturing equipment, and specialist electronics for demanding applications (aerospace, defence, automotive).
• Advanced manufacturing: Additive manufacturing, precision engineering, robotics, and production automation.
• Materials science: Novel materials with applications in construction, packaging, textiles, or industrial processes.
• Space and defence: Satellites, launch systems, and dual-use technologies with commercial and defence applications.

Notably, this is not a fund for digital or software-as-a-service businesses, regardless of how innovative they are. If you're building a SaaS platform for manufacturing logistics or an AI model for predictive maintenance, traditional venture capital firms are better-suited investors. Longwall backs the hardware, the chemistry, the biology, and the physics—the stuff that requires longer timelines and carries deeper technical risk.

For operators evaluating whether Longwall might be a fit, the key question is: Does my business require sustained R&D investment, extended validation timelines, regulatory navigation, or bespoke manufacturing before reaching commercial viability? If yes, Longwall becomes relevant. If your business model relies on software iteration and user acquisition, it's worth targeting mainstream venture firms first.

How to approach Longwall and deep tech fundraising in practice

If you're a UK deep tech founder considering the Longwall fund, here's what the investment process typically looks like, and how to prepare:

Stage 1: Pre-seed to Seed (£250k–£2m)

Before approaching Longwall, most deep tech founders spend 12–24 months de-risking the core technical hypothesis. This might involve:

• Publishing peer-reviewed research or technical whitepapers to validate underlying science.
• Building a prototype or minimum viable demonstration that proves the concept works at laboratory or bench scale.
• Securing founder-led grants from Innovate UK, research councils (UKRI), or industry partners to fund this early-stage work.
• Recruiting a technical co-founder or advisory board with deep expertise in your domain.

At this stage, your investor base typically includes angels, perhaps some institutional angels from networks like the Tech UK community, and possibly early-stage grants. You're not yet fundraising from Longwall, but you're building the credibility story that will matter when you do.

Stage 2: Seed to Series A (£2m–£8m)

Once you've de-risked the core science, moved beyond proof-of-concept, and ideally attracted interest from strategic partners or early customers, the Longwall fund becomes relevant. At this stage, you'll typically:

• Engage a venture capital adviser or experienced deeptech operator as an informal mentor to help shape your fundraising narrative.
• Prepare a detailed investment memorandum covering: the technical innovation, the addressable market, the path to commercialisation (including regulatory timelines if relevant), the capital required to reach the next inflection point, and the team's track record.
• Identify warm introductions to Longwall partners through existing investors, UK accelerators focused on deep tech (like SFC Ventures), or sector-specific networks.
• Be explicit about your use of capital: £2m for expanding a pilot manufacturing facility, £1m for clinical trials, £500k for regulatory certification—specificity matters.

Longwall is a relatively small team, so direct outreach without a warm introduction is unlikely to gain traction. Instead, work through your existing network: existing angels, corporate partners, accelerator alumni networks, and university technology transfer offices are all credible sources of introductions.

Stage 3: Investment and post-investment support

Once Longwall leads (or co-leads) a round, the firm takes a hands-on approach typical of deep tech specialists. This includes:

• Board seat or board observation rights.
• Introductions to supply chain partners, manufacturers, and distribution partners relevant to your sector.
• Connections to later-stage funding sources, including corporate venture arms and growth capital firms, once your technology reaches later-stage validation.
• Support navigating technical and commercial milestones without pressure to hit arbitrary user-growth metrics.

One misconception founders should avoid: venture capital, including Longwall's, is not a substitute for strong unit economics and a clear path to profitability. The longer timelines and deeper technical risk tolerance do not mean investors will back ventures with unlimited burn or unclear commercial viability. If anything, deep tech VCs scrutinise path-to-profitability more carefully than mainstream VCs because the exit windows are longer and the downside risk is higher.

The broader policy context: Why the British Business Bank is betting on deep tech now

The Longwall fund doesn't exist in a vacuum. It's part of a broader UK industrial strategy realignment toward supporting hard innovation and manufacturing competitiveness.

Over the past decade, UK venture capital has become increasingly concentrated in software and digital services, particularly in London. This is efficient capital—software scales quickly and exits happen within 7–10 years. But it's also left the UK with a fragmented deep tech funding ecosystem, with gaps between seed funding and institutional capital, and insufficient late-stage venture capital for scaling hard tech companies.

The British Business Bank, in collaboration with the Department for Business, Energy and Industrial Strategy (now the Department for Science, Innovation and Technology), has identified this gap as a strategic vulnerability. If the UK wants to maintain competitiveness in semiconductors, green energy, life sciences, and advanced manufacturing, it needs institutional capital that can back founders through extended development cycles.

The Longwall investment signals a shift: the British Business Bank is moving beyond simply guaranteeing bank loans (the Start Up Loans scheme) or funding early-stage grants (Innovate UK). It's now directly investing public capital in venture funds that take equity stakes and support scaling. This is a more interventionist approach, but it's justified by the long-term strategic importance of maintaining UK innovation capacity in sectors critical to economic security and climate targets.

For founders, the practical upshot is this: if you're building deep tech, the UK funding environment is improving. The barriers are still significant—you'll still need a strong technical team, genuine intellectual property, and a credible path to commercial viability—but the institutional backing is now in place to support ambitious ventures that might have been impossible to fund three years ago.

What deep tech founders should prepare now

If you're a UK deep tech founder and you believe Longwall might eventually be a relevant funding source, here are the concrete steps to take now:

Build your intellectual property and technical credibility

Publish research findings, file patents where appropriate (and understand the trade-offs between early publication and patent timing), and ensure your technical team has a track record of delivering complex engineering projects. Longwall backs founders and teams with provable expertise, not just good ideas.

Secure non-dilutive funding early

Use Innovate UK grants, SEEDED competitions, and other UK research and innovation funding to fund early-stage R&D without diluting equity. This extends your runway and strengthens your position when approaching venture capital later.

Connect with your sector's ecosystem

Join relevant trade associations, attend industry conferences, engage with corporate innovation teams, and build relationships with potential customers. Longwall backing is more likely when you've already validated demand with strategic partners.

Recruit an experienced co-founder or CTO if you lack one

If you're a technical founder working solo, bring on a commercial co-founder or experienced operator early. Deep tech ventures are complex to navigate commercially, and investors want to see balanced teams with complementary skills.

Prepare detailed, realistic financial models

Deep tech investors scrutinise unit economics, manufacturing costs, regulatory timelines, and path to profitability more closely than mainstream VCs. Have robust financial models built by someone with relevant industry experience, not just enthusiastic spreadsheets.

The risks and limitations: What the Longwall fund does not solve

It's worth being clear-eyed: a £100 million fund is meaningful but not unlimited. Divided across 15–25 companies, the average cheque is £4–6 million. If you're building a chip fab, a large-scale biotech platform, or an aerospace component manufacturer, you'll likely need multiple rounds, subsequent funds, or corporate partnerships to reach full commercialisation. Longwall is a crucial bridge funding source, not the full solution.

Additionally, the fund is concentrated on the most promising technical talent. If your team lacks published track records or relevant domain expertise, Longwall will pass, regardless of market opportunity. The firm is backing founders and teams, not just ideas.

Finally, the fund's success ultimately depends on exits. Deep tech companies take longer to exit (10–15 years versus 7 for software), and the exit opportunities for hardware and biotech are more constrained (strategic acquisitions are more common than IPOs). This means returns will likely be lower and more variable than software venture capital, and the fund's long-term viability depends on demonstrating that patient, specialist capital can still generate institutional returns. If Longwall's portfolio companies fail to deliver meaningful outcomes, future deep tech funding from the British Business Bank and other institutions will become harder to secure.

Conclusion: A shift in UK startup funding priorities

The British Business Bank anchoring Longwall's £100 million deep tech fund represents a meaningful evolution in UK startup funding. For the first time, there is an institutional-scale capital source explicitly designed to back the kind of ambitious, long-timeline, technically complex ventures that have historically struggled to find venture backing in the UK.

This doesn't mean deep tech founders should suddenly find fundraising easy. The competition remains intense, the technical bar remains high, and the path to profitability remains critical. But it does mean that if you're building genuine deep technology with real technical innovation, a credible team, and a clear commercial pathway, there is now an institutional investor explicitly set up to support your journey from prototype to scale.

For UK founders in hard tech, climate, life sciences, semiconductors, and advanced manufacturing, Longwall and funds like it represent a recognition that innovation isn't just about fast-scaling software. It's also about the slower, harder, more essential work of building new materials, new manufacturing processes, new medicines, and new energy systems. The British Business Bank's commitment to backing that work is a significant step forward for UK competitiveness and industrial strategy.