Tho' this is something that it's impossible for governments to do, really, all the money will be creamed off by "advisers" and "consultants", small companies given impossible bureaucratic hoops to jump through, etc. The best thing the government can do is just take a step back.
Or my pet harebrained scheme: resurrect the original Acorn Archimedes and buy a million of then, requiring that all govt departments use indigenous British computing technology...