TSB is set to fall into Spanish hands after the UK challenger bank said it was prepared to back a takeover offer valuing the business at £1.7 billion.

The proposal from Banco de Sabadell comes less than a year after TSB rejoined the London stock market in a split from Lloyds Banking Group.

TSB said its board was minded to back Sabadell's 340p-a-share offer and added that its ownership would help accelerate TSB's growth strategy.

The deal's success will hinge on the response of Lloyds, which still owns 50% of TSB and has to dispose of the remaining stake by the end of this year.

Sabadell, which has a presence in the United States, pledged to keep the TSB brand name and create a "robust competitor" in UK banking.

In a joint statement with TSB, it said the UK was an attractive market for future investment and promised to draw on its experience in the Spanish banking market and in small and medium-sized business lending.

The statement added: "Sabadell believes that the two companies share similar values and customer commitment."

TSB has 8,600 staff and 631 branches.