I think you can safely resolve this as NO.

https://www.tokamakenergy.co.uk/2023/02/10/tokamak-energys-new-advanced-fusion-prototype-to-be-built-at-ukaeas-culham-campus/

They changed their plans. ST-F1 is not mentioned on their website anymore. Instead they are building ST80-HTS, and it's not going to be complete before 2026. Breakeven is not mentioned as a goal and overall wording is more about testing hardware components, not achieving plasma parameters, which is a bad sign IMO. Also it typically takes tokamak years before its construction and operation at optimal parameters, so even if they start operating it in 2026 and breakeven was technically possible at this machine (which I really doubt since they don't mention it anymore), I would not expect it before 2027.

So unless you work there and have some reasons to believe that they will magically build it in 2 years instead of 3 (which never happens with these things), there are no reasons not to resolve it now.

@BairAiushin thanks for the research and insight! I don't work there or have any reason to believe this will happen, I created markets with the same criteria for all the major fusion companies.

@ahalekelly I would choose the date that gave all contenders some chance then. Anyway, your markets, your rules.

They aim to demonstrate energy gain in their next device, a fusion power demonstrator named ST-F1, set to be built by 2025.

https://iopscience.iop.org/book/edit/978-0-7503-2719-0/chapter/bk978-0-7503-2719-0ch5
Published December 2020