Santander has reported a knock to annual profits from a new £450m provision for mis-selling payment protection insurance (PPI) in Britain - its biggest market.
The group's UK arm reported a 4.1% fall in pre-tax profits to £1.3bn - saying they would have risen had it not booked the PPI charge in its final quarter.
Fourth quarter figures showed an £82m loss for the UK business, from profits of £496m in the same period last year.
Santander said it was raising its provision as the Financial Conduct Authority plans to set a two-year deadline for mis-selling claims, which banks believe will lead to a final rush of settlements.
The industry has set aside £28bn to date.
Santander reported a 3% rise in group profits and a "solid" performance in the UK during 2015.
It said net UK mortgage lending - total new loans less repayments - rose by £2.7b in 2015, with overall new lending of £26.5bn.
Nathan Bostock, chief executive of Santander UK (LSE: 44RS.L - news) , said: "We anticipate that the UK economy will remain supportive of our business in 2016, but are mindful of the recent market volatility from macro/geopolitical factors, and that our future earnings will be impacted by the bank corporation tax surcharge."