The NVIDIA GeForce RTX 5090 is one of the most power-hungry graphics cards in the world. With a base TGP of 575W, you need a very powerful power supply to run it. However, the latest leaked prototype of the RTX 5090 suggests it could have been even more demanding. Four Power Connectors for More Power https://twitter.com/yuuki_ans/status/1926903505274433943 According to the leak that includes a photo of an early prototype of the RTX 5090, this version of the card had no less than four 16-pin power connectors. This setup would allow the card to draw up to a shocking 2,400W of power,
3840W per breaker. Minus 2400 leaves 1440W, for a CPU, the minor components, and monitors/other equipment. In theory it could work.
You would still need to run the computer off multiple plugs, as almost any 240v plug is 10a.
You’d likely need a dedicated breaker and plug, similar to a stove plug.
All UK plugs are 13A.
Here, plugs are 230V and 16A = 3680W. Not quite as much as I thought (most extension cords seem to be rated for a bit more, which makes sense), but definitely enough to run monitors of the same breaker.