Benefit Fraud versus the rest

Benefit and Tax Credit fraud = £1.6bn
UK government figures for 2012 estimate benefits overpaid due to fraud is £1.2 billion and tax credit fraud is £380 million. So just under £1.6 billion in total; less than 1% of the overall benefits and tax credits expenditure and less than benefits underpaid and overpaid due to error.
SOURCE: HM Government National Fraud Authority

Non "bailout" support to banks = £50bn
Excluding the bailout, it still costs the taxpayer £50bn a year to insure the banks against failure.
SOURCE: Bank of England.

All UK fraud = £73bn
The UK government estimates that total fraud (public, private and business) across the whole of the economy amounts to £73 billion a year.
SOURCE: HM Government National Fraud Authority

Tax dodging = £120bn
HMRC estimate for tax evasion and "aggressive" avoidance = £30bn+
Tax Research UK says this is a gross underestimate, and puts the figure at £120bn
SOURCE: Tax Research UK

And just for the record...

The Bank of England admitted its £375bn of Quantitative Easing gave a £600bn asset boost to the richest 50%. The richer you are, the more of it you got. Fortunately, it doesn't happen every year!
SOURCE: Bank of England