LIVERPOOL, England - Britain's main opposition party leader Keir Starmer said on Sunday he would reintroduce the top rate of income tax to 45% after the government abolished the rate in a mini-budget.

Starmer is under pressure to assert himself as the prime minister-in-waiting as he starts his campaign for power at this week's annual Labour conference in Liverpool in northwest England.

The Labour leader said the move to cut the top rate of tax was unfair because it handed someone earning 1 million pounds ($1.09 million) a 55,000 pound tax cut.

"I would reverse the decision they made," Labour leader Starmer told the BBC. "It is hugely risky, it is hugely divisive, and I would reverse it."

Labour will use this week's conference to set out dividing lines on key policy issues after the government announced large tax cuts, huge increases in borrowing and the scrapping of caps on bankers’ bonuses.

However, Starmer said a Labour government would not reverse the government's decision to cut the basic rate of income tax to 19% from 20%.

"I’ve long made the argument that we should reduce the tax burden on working people so no we wouldn’t reverse that," he said.

(Reporting by Alistair Smout and Andrew MacAskill)