Democracy isn't about changing Governments every few years, democracy is about finding the rulers that the people want ruling them. If the electorate decides that the Tories are the best party out there, for whatever reason, then it's perfectly reasonable that they should be able to stay in power for as long as they're voted for.

Alas, there's a huge democracy deficit in this country, anyway. The system favours a two party state (whichever those two parties may be), and it's also inherently biased towards Labour at the moment, though I'm sure the Conservatives will try and change that as much as possible when they get into power next year.

ok then, how would another party challenege them if Labour diminish significantly then?

Another party would rise from Labour's fall. If Labour was to die in a major way, then you would see some of the more centrist Labour MPs jumping into the Lib Dem boat, you could also see three or four smaller parties form that would probably operate under a coalition.

This is all hypothetical, mind you. If Labour was to really become unpopular, it would probably just change a lot of its policies to be closer to what the public wants (like it did in 1997).

what do the public want?

we come back to turnout, thoose that dont vote, well, we dont know what they want, lol, so we need to find out, is i assume what your getting at?