The BoE said its plans would leave the average amount of capital that lenders need to hold broadly unchanged, but would allow it to vary more during the course of an economic cycle.

"These changes improve the responsiveness of capital requirements to economic conditions by shifting the balance ... towards buffers that can be drawn down as needed," BoE Governor Mark Carney told a news conference.

Major British lenders currently hold so-called Tier 1 capital equivalent to just under 14% of risk-weighted assets on average.

The BoE designates 1% of risk-weighted assets as a 'counter-cyclical capital buffer' (CCyB) during normal economic times, which can be used to support lending in a downturn.

On Monday the BoE said it would double this buffer to 2%, to take effect by the end of 2020, and then lower other capital requirements by a similar amount.

This would allow major British lenders to absorb up to 23 billion pounds ($29.5 billion) of losses in a downturn without restricting lending, supporting up to 500 billion pounds of loans to British homes and businesses - the equivalent of five years' borrowing.

Reuters reported last week that Britain's mid-tier banks had asked the BoE to ease rules they say make it difficult for them to compete with the likes of HSBC, Barclays, RBS and Lloyds on an equal footing. [nL4N28J2LA]

The BoE said on Monday that when it consults on the detail of the CCyB changes, it would try to ensure they did not lead to any net increase in smaller banks' capital requirements.

For larger banks, the BoE said the changes would increase Tier 1 capital requirements by about 0.35 percentage points to just over 14%.

STRESS TESTS PASSED

Alongside this, the BoE said all of Britain's seven main lenders passed an annual test of their ability to withstand financial and economic shocks for the second year running.

The BoE tested HSBC, Barclays, Lloyds Banking Group, Royal Bank of Scotland, Standard Chartered, Santander UK, and Nationwide Building Society for their ability to withstand financial market stresses.

The BoE said no lender failed to meet a firm-specific hurdle for the minimum amount of capital at the end of the test, in a repeat of last year's result on a test that was similar in toughness.

"UK banks are well above capital required hurdle rates and as a result, capital distributions through dividends and stock buybacks should increase," said Fernando de la Mora, managing director at business consultants Alvarez & Marsal.

All the banks in the stress tests said they would not need to find fresh capital as a result of the tests.

The BoE said Barclays and Lloyds would need to convert some of their AT1 capital into equity during a stress scenario, if new accounting rules that fully take effect in 2023 were applied.

The BoE had already said lenders held enough capital to cope with the harshest form of Brexit, though a cliff-edge departure that would severely damage the economy now looks off the table for Jan. 31.

Britain's newly re-elected government has a comfortable majority to push through a divorce settlement that will see Britain leave the bloc at the end of next month and enter an 11-month transition period that lasts until the end of 2020.

($1 = 0.7794 pounds)

By David Milliken and Huw Jones