The Telegraph reports that the National Audit Office (NAO) has identified that the UK has paid £0.4BN in fines to the EU, and that there is a further £0.6BN that has been set aside for future fines.
These fines are the cost to the taxpayer of implementing EU schemes in the UK. It seems that when the EU decides that the financial management of a scheme is inadequate it withholds future funds (a form of fine), the shortfall for which the UK government is forced to make up from its own (ie taxpayers') funds.
Whether or not the UK should really be "fined" in this manner is open to question, given that the EU is hardly an example of financial probity, honesty or financial transparency and budgetary control.
Only when the EU receives an unqualified audit report, and implements effective and proactive financial controls that prevent the ongoing and widely documented financial abuse by member states and MEPs, can it be in a position to dictate to the UK what constitutes effective financial control.