Astral Systems, a Bristol deep-tech firm, raised a £23m Series A to manufacture medical radioisotopes using its multi-state fusion reactors {{SRC:6}}. The isotopes, Actinium-225 and Lead-212, are used in targeted cancer therapy, and the world produces them in a handful of ageing reactors. Mercia Ventures, a UK regional venture capital firm, led the round, with Tees River, Daphni, Blast Club, Speedinvest and Playfair Capital joining.
Astral runs several small fusion reactions at once rather than chasing grid power from one large tokamak, and it uses those reactions to breed isotopes that decay too fast to stockpile. That method attacks a supply bottleneck, because current output depends on a few reactors built decades ago, any one of which going offline can strand a therapy. Deep-tech investors, not energy utilities, backed the round, since the product on sale is a scarce medical input rather than electricity.
A lab-to-market round of this size lands rarely, and when it does it moves a region's annual figure on its own. This is part of the South West's outsized 2025 swing, the kind of single large cheque that lifts a regional share one year and vanishes the next. Unlike CuspAI's foreign-only cap table, this round kept a UK lead, and it lands in the same Bristol cluster where mycelium-materials firm Mykor raised £4m earlier in the cycle .
