The bailout of Ulster Bank cost British taxpayers more than stg£10 billion pounds - or €11.7 billion.
That is about a quarter of the total amount of money Britain spent rescuing the Ulster Bank parent company Royal Bank of Scotland (RBS).
The startling figures comes amid a push in recent weeks to try and get the Irish government to take on Ulster Bank. The Taoiseach Enda Kenny last week rejected a proposal to take control of Ulster Bank in return for the UK buying some NAMA loans.
The revelation of the figures needed to prop-up Ulster come as the British Banking Standards Commission makes its findings on the future of RBS public this week.
The frontpage of The Times today
RBS is 81% owned by the British government. They desperately want to get rid of their stakes in RBS and Lloyds Bank. The drag of injecting so much money into Ulster Bank could hinder that.
Ulster Bank has been heavily loss-making for RBS, after lending billions of euro to developers here.
Ulster is the third-largest bank in the country. Last week, its chief executive Stephen Hester told the Irish Independent that the bank was not for sale.
Newstalk's Business Editor Ian Guider told Breakfast the British government are looking to Ireland for help.
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