British Design Fund
British Design Fund is a London-based venture fund that backs purpose-led British product and manufacturing start-ups. It is not a water fund, but three of its hardware bets, from sewer sensors to a low-energy hot-water pipe, sit squarely in water. As of December 2025 it secured a £5 million commitment from the British Business Bank.
Compiled by Antoine Walter, (don't) Waste Water, from official filings and direct intelligence in Leviathan.
The take
British Design Fund is the rare investor that cares less about the software and more about the thing you can actually hold in your hand. It backs purpose-led British product, design and manufacturing start-ups, the kind of physical-product companies most venture funds quietly avoid, and it does it through UK tax-advantaged SEIS and EIS funds (government schemes that hand early-stage investors generous tax relief for taking the risk). As of December 2025 it secured a £5 million commitment from the British Business Bank through the Regional Angels Programme, money earmarked to widen its backing of product founders outside London.
British Design Fund is not a water fund, which is the first thing a newcomer should know before reading its water deals. Water is a thin but telling thread: three of its portfolio companies solve water problems, and all three are hardware, not apps. ManholeMetrics builds low-cost sensors that catch sewer flooding before it happens; Water Kinetics makes an Eco-duo pipe that recirculates hot water on roughly half the energy and starves Legionella of the warmth it needs; and Untap Health turns a building's wastewater into a real-time early-warning system for infectious disease. That is the pattern in miniature, an engineered object you can manufacture rather than a dashboard.
British Design Fund grew out of product entrepreneurship, not finance, and it shows. Co-founder and chief executive Damon Bonser spent years sourcing, designing and selling physical products before he turned investor, and chair John Mathers once ran the UK's Design Council, so the fund treats good design as a way to de-risk an early-stage bet rather than decorate it. To my eye that is what makes its water names worth tracking: British Design Fund has led most of those rounds, writing the first serious cheque into unglamorous British water hardware that a generalist software fund would never look at twice.
Water Commitment Score
Compiled from official filings, third-party records, and direct intelligence from investors and founders, in Leviathan · recomputed monthly · as of Jun 2026.
How they invest
Portfolio · 3 water companies
Frequently asked
- What does British Design Fund invest in?
- British Design Fund backs purpose-led British product, design and manufacturing start-ups at pre-seed and seed, the earliest stages of a company. It looks for strong intellectual property, proven demand and global ambition, investing through UK SEIS and EIS tax-advantaged funds across health, sustainability and assistive technology, with a focused thread of water-hardware companies.
- What water companies has British Design Fund backed?
- British Design Fund has backed three water companies and led most of those rounds: ManholeMetrics, whose low-cost sensors catch sewer flooding before it happens; Water Kinetics, which makes a low-energy hot-water recirculation pipe; and Untap Health, which reads a building's wastewater to flag infectious-disease outbreaks early. All three are physical hardware, not software.
- Who runs British Design Fund?
- British Design Fund was co-founded by chief executive Damon Bonser, a serial product entrepreneur, and is chaired by John Mathers, former CEO of the UK Design Council. Its funds are run by FCA-authorised Sapphire Capital Partners, with Boyd Carson as fund manager and David Kremer chairing the investment committee.
- Where is British Design Fund based?
- British Design Fund is based in London, at Queen Street Place in the City, and invests in product start-ups across the United Kingdom, from the South West to Scotland. Its December 2025 British Business Bank backing, through the Regional Angels Programme, is aimed specifically at product founders outside London.
- Is British Design Fund a water-focused fund?
- No. British Design Fund is a generalist early-stage product and manufacturing investor, not a water specialist. Water is one thread inside a much larger portfolio of physical-product companies. Its three water investments, all hardware, reflect a product-design thesis rather than a dedicated water mandate.