However, applications increased by 142 per cent in the fourth quarter compared to the previous three months and the bank said it was entering 2019 with a strong completion pipeline.
It also highlighted that it’s new IT system allowed brokers to submit applications in half the time compared with the old system.
“TSB has already started to see the benefit with the busiest ever week in the bank’s history for mortgage applications in December 2018,” it said.
Its mortgage portfolio loan-to-value (LTV) remained “conservative” at 44 per cent.
IT failure costs £330m
Overall TSB reported a pre-tax loss of £105.4m with costs from the IT failure including customer compensation, additional resources, fraud and lost income of £330.2m.
It expects to recover £153m of this from its IT provider, Sabis.
However, despite the IT failure the bank gained more customers than it lost.
Around 80,000 customers switched their bank account away from TSB in 2018 with volumes peaking in Q2, compared with 50,000 customers switching away in 2017.
In contrast, 140,000 customers opened a new bank account or switched their account to TSB in 2018.
In 2017 the lender recorded a pre-tax profit of £162.7m with gross mortgage lending of £7bn.
‘Most challenging year’
TSB executive chairman Richard Meddings said: “2018 was TSB’s most challenging year and we are sorry for letting our customers down.
“Looking forward, we’re now a stronger bank for our experience, with a trusted brand, able to serve more customers in more communities than ever before.”