bro you need to wake up. this is not how software works with government. NHS is not going to write their own Linux distro. that's crazy even for a company to do. its gonna take them a recurring budget every year just for maintaining the system. it'll balloon way past the Microsoft number easily. 163mm pound is a tiny TINY budget for an undertaking like building a healthcare OS that they plan to maintain forever. they'll have money to hire contractors once, then they'll pass it to their internal teams that are staffed with people trying to pass time until they collect pension.

also no way will any agency take the liability of building a custom OS for their health infra. health tech is honestly one of the hardest, most expensive things to dev just due to all the regulation and red tape behind it. you can't just build health tech for the hell of it, even if you're the NHS. it takes years and years and crazy money to have your systems certified to handle health data even if you're building internally.