This year's stress tests of Britain's major banks will not become an excuse for regulators to ratchet up capital requirements without justification, a senior Bank of England official has said.

The annual stress tests are designed to check banks have enough reserves to cope with future financial shocks so they will not need to be rescued using taxpayers money.

Alex Brazier, executive director for financial stability strategy and a member of the Bank of England's Financial Policy Committee risk watchdog, said the central bank was mindful of how setting capital requirements had real economic consequences.

He said: "It is incumbent on us not simply to ratchet up, or down, the severity of the stress scenario over time.

"As policymakers, we have a responsibility to ensure that capital requirements change only because the risks change.

"The side of the bed we exited on the morning of deciding the scenario should not feature in that dataset. It hasn't before. And this approach ensures it won't in future."