By Sumeet Desai and Jodie Ginsberg

LONDON (Reuters) - Britain committed billions of pounds to a multi-pronged rescue plan for its banking system on Wednesday and joined other major economies in cutting interest rates to tackle the global financial crisis.

In a sweeping move that Prime Minister Gordon Brown said was as bold as a $700 billion (404 billion pound) U.S. bailout, the government said it would provide at least 50 billion pounds to immediately increase capital available to struggling high street banks.

"We have led the world today with a proposal to restructure our banking system," Brown said after emergency overnight talks with banking chiefs. "We are taking the steps that I believe that other countries will take in the future."

The talks followed a day of dramatic falls on Tuesday in the shares of banks threatened by a global collapse in financial confidence that has choked off lending -- the lifeblood of the economy at large.

The banks' troubles have raised popular fears of a bank crash and lost savings, while the wider shockwaves now imperil jobs and industry around the world.

Just days after the U.S. approved a rescue of its crisis-hit financial system, the government announced it would buy new shares in banks, guarantee up to 250 billion pounds to help them refinance debt, and make at least 200 billion pounds of liquidity available to the market.

The bank support plan was announced just hours before a co-ordinated 0.5 percentage point cut in key interest rates around the world led by the U.S. Federal Reserve.

German deputy Finance Minister Joerg Asmussen said Britain's plan would help financial stability in Europe.  Continued...