Santander saw its mortgage lending increase by £2.3bn in the first six months of the year, reaching £157.2bn at the end of June.
This represented 1.5 per cent growth when compared with December’s figures of £154.9bn.
Santander's results said the bank registered higher mortgages approvals driven by "management pricing actions" and a focus on customer service and retention.
For the rest of 2018, Santander is expecting modest growth in its core lending markets, with the mortgage market likely to grow around 3 per cent in 2018 with "weaker buyer demand and subdued house prices seen to date likely to continue".
Nathan Bostock, Santander’s chief executive, said: "We have continued to deliver for our customers in a competitive market with strong net mortgage growth to UK homeowners and focused lending growth to trading businesses, driven by an emphasis on customer experience and loyalty."
Overall, the bank saw its profits over tax drop 15 per cent year-on-year, from £1.06bn to £903m at the end of June, due to a "competitive and uncertain" operating environment.
The bank's total operating income fell 8 per cent during the period, from £2.5bn to £2.3bn.
Mr Bostock noted, however, that the progress made recently was "encouraging", with profit before tax of £489m, up 18 per cent quarter-on-quarter, with some improvement in costs.
He added: "Our investment in business transformation initiatives also continued despite significantly higher regulatory, risk and control spend for projects, such as GDPR, PSD2 and Mifid II."