Aug 1 (Reuters) - Metro Bank Holdings on Tuesday reported a first-half profit compared with a year-ago loss, helped by the British mid-sized lender keeping a tight rein on costs and benefiting from interest rate hikes.

Bank profits have been lifted by successive rate increases by the Bank of England, enabling lenders to make more money on borrowing despite the threat to the economy posed by rampant inflation.

Still, political pressure to help struggling savers are taking the shine off plumper revenues from higher interest rates. It has also raised borrowing costs and pushed customers to repay debt and switch to savings.

The bank posted an underlying pre-tax profit of 16.1 million pounds ($20.65 million) for the six months ended June 30, compared with a loss of 48 million pounds a year earlier.

Metro Bank, which was set up more than a decade back to challenge the dominance of mainstream lenders, reported total deposits of 15.53 billion pounds, down from 16.01 billion pounds as on Dec. 31.

($1 = 0.7798 pounds) (Reporting by Eva Mathews in Bengaluru; Editing by Rashmi Aich)