Santander reported gross mortgage lending of £25.5bn in 2017, down from £25.8 in 2016.
At the same time pre-tax profit fell by 5% to £1.81bn, down from £1.95bn.
Nathan Bostock, chief executive officer, said: “I am pleased to report a solid performance for 2017 with Santander UK continuing to demonstrate resilience.
“We delivered higher income, cost discipline and balance sheet strength, while making steady progress towards meeting our strategic and operational goals.
“Profitability was impacted by the losses incurred on our exposure to Carillion, which offset otherwise strong growth. We are working closely to support customers who have suffered from their collapse.
“We have continued to improve our offering for customers, with products and services tailored to suit their needs and delivered in a way that works for them.
“In addition, we supported our corporate customers with increased lending to other business sectors except in commercial real estate where we managed our exposure.”
Mortgage gross lending was £25.5bn, £300,00 less year-on-year. It retained about 78% of mortgages reaching the end of their incentive period but the proportion of SVR loan balances decreased to 15%. This includes attrition of £5.5bn, down from £7.0bn in 2016.
This was driven by customer refinancing and sentiment over expected future interest rate movements.
Santander sold homes to 24,000 first-time buyers, reported £4bn of gross lending, its interest-only mortgage balances decreased £3.2bn to £49.1bn and buy-to-let mortgage balances rose by £0.2bn to £6.8bn.
In 2017, it completed 7,500 buy-to-let mortgages, representing 6% of the value of its new business flow, at an average LTV of 61%.
No new business was written above 70% LTV and 91% was written at or below 60% LTV, while this was 95% in 2016.
Profit before tax was £1,814m, down 5% year-on-year and adjusted profit before tax was reported at £1,952m, down 4% year-on-year.
Bostock added: “Despite the uncertain environment we are fulfilling our purpose to help people and businesses prosper and to support the wider economy.”