Banks are the life blood of the UK....if you had allowed major banks to fail the resulting panic would have been horendous. Banks all lend to one another...thats how they fund their day to day business and to enable that function to work correctly they have to have trust in one another. Failing banks would errode that trust and the banks would effectively shut up shop....that in turn would stiffle money being lent to businesses, who in turn would find vital working capital being turned off, ie overdrafts, business loans etc and many companies would have gone to the wall and in the process 000's of people would have lost their jobs.
We could have then found ourselves in a lost decade, where banks are afraid to lend and the whole banking system would have been paralised due to lack of trust, causing further company failures and massive job losses.
I am no lover of the banks for their mis-management and the greed that they have shown, but pumping money into them has been a necessary evil......we will eventually get this money back as the shares that the Government hold in these banks will be sold at some stage...they may even end up making a profit, as the share prices of these banks will eventually recover, although that will be some time off.