The agreement sees Barclays take on 1.5 million new customers, deposits of £10.9 billion and a mortgage book with outstanding balances of £5.6 billion, further consolidating a market that the government has called for more diversity in.

ING Direct UK's 750 employees will transfer to Barclays, integrated into the latter's UK retail and business banking division.

Jan Hommen, CEO, ING, says: "In Barclays we have found a company who will continue to provide the excellent service our approximately 1.5 million ING Direct customers in the UK have grown accustomed to."

ING will make a EUR320 million loss on the deal - slated to close in the second quarter, subject to regulatory approval - but release capital of EUR330 million.

The firm has been busy selling off assets over the last year to raise cash to pay back money lent by the Dutch government at the height of the financial crisis. In August it agreed to offload its Canadian online unit to Scotiabank for C$3.1 billion deal while its US operations have been sold to Capital One.