breadandbutterfly All four were ministers of state - one under the Conservatives, three under Labour (although their party allegiance has little to do with why I picked them).
Edwina Currie was gaff prone who, as a Health Minister, caused a blind panic over the safety of eggs and their links to salmonella - this was later demonstrated to be untrue but by then, the damage had been done and many farms went bust.
Estelle Morris admitted herself that she wasn't up to the job. That's a very brave and honest thing for a politician to say but it hardly makes them competent.
Hazel Blears was also gaff prone, largely ineffective and is best remembered for being one of the foremost MP's for fiddling her expenses.
Caroline Flint, who as Mister for Europe, later admitted that she'd never read the Treaty of Lisbon - despite being the minister responsible for overseeing the introduction of the treaty.
Each of these was elevated to the cabinet so one can only assume that at that time, the respective leaders of their parties thought that they were the best people for the jobs.
By permanent, I meant that instead of acceding to their roles on whatever merit they were thought to have, under a quota system, there is even less pressure on them to remain in post. The permanence derives from the fact that there are fewer people to replace them.
As a final point, the whims of the electorate have nothing to do with ministerial selection. If they did, there would be no way that Mandy, twice as an MP and finally (without even a seat in the House of Commons) as Baron Mandelson, would have been made a cabinet minister.