London’s AI infrastructure startup Callosum has landed a £73.5m seed round, dominating a week in which UK tech investment plummeted 72% week-on-week.
UKTN tracked £102.95m across nine funding rounds between 17 and 21 August. The sharp drop from the previous week’s total underscores how a single large deal can swing the market when overall activity remains thin.
Callosum, founded in 2026, builds heterogeneous computing systems software. Its platform pairs specific AI tasks with the most cost-efficient models and silicon available, tackling the growing cost and energy burden of running advanced AI workloads. Backers include Atomico, Plural, DCVC, the UK Sovereign AI Fund, and several angels.
Meanwhile, hybrid-electric aviation startup Ampaire secured £14m in Series B funding. The London company, founded in 2017, develops retrofit propulsion systems and auxiliary power units for commercial aircraft, aiming to cut emissions, fuel consumption, and operating costs. Investors include IAGi Ventures, Alaska Airlines, and DiamondStream Partners.
Ampaire’s raise stands as the week’s second-largest. The climate tech sector otherwise saw limited action across the tracked rounds.
In edtech, Medly AI pulled in £5.9m. The London-based startup, founded in 2025, operates an automated tutoring platform that adapts to individual student learning styles for GCSE and school exam preparation. Felix Capital, Eka Ventures, Ada Ventures, and angels participated.
Deep tech made a showing with Plymouth’s Oshen raising £3.65m. The 2022-founded company builds autonomous ocean-sensing robotic vessels powered by wind and solar, delivering real-time maritime data to navies, researchers, and weather agencies.
Newcastle fintech Noggin HQ collected £2.3m for its alternative credit scoring system. The 2021 startup uses open-banking transaction data to assess cashflow, serving consumers underserved by traditional credit models.
Edinburgh’s Singular Photonics added £1.6m for its single-photon avalanche diode image sensors, targeting machine vision, robotics, and medical imaging.
Colchester agtech Versatile RobotX raised £1m for its autonomous crop-handling robots, offered under a Robotics-as-a-Service model to address farm labour shortages.
Aberdeen semiconductor firm HexSeed secured £600,000 to convert captured CO₂ into synthetic diamond coatings for GaN power chips, preventing overheating in AI data centres.
EcoNomad, based in Harpenden, closed the week with £400,000 for its modular anaerobic digestion systems that turn farm waste into biogas and biofertiliser.
