The National Audit Office has just published a report on the Northern Rock. The NAO estimates that the ultimate cost to taxpayers of bailing out the Northern Rock will be £2 billion. That comes to £67 for each of the 29.7 million taxpayers in the UK. Of course, this cost ignores other "taxes" such as the higher inflation due to quantitative easing.
£67 doesn't sound like much, but Northern Rock was a small bank compared to RBS, Lloyds-TSB and HBOS, the three big banks which failed in 2008. In terms of deposits, these three banks, taken as a whole, were 27 times larger than Northern Rock.