The International Monetary Fund lowered its global growth outlook yesterday because of turmoil in the financial markets and a slowdown in America.

The US economy, which the IMF described as “the epicentre of the global slowdown”, will expand by 1.5 per cent this year, down from a previous forecast of 1.9 per cent.

The IMF said: “The financial market strains originating in the US sub-prime sector – and associated losses on bank balance sheets – have intensified, while the recent steep sell-off in global equity markets was symptomatic of rising uncertainty.”

The global economy is poised to grow 4.1 per cent this year, down 0.3 percentage points from a previous estimate, the IMF said in a quarterly update of its biannual World Economic Outlook. Economic growth in the eurozone for this year was revised to 1.6 per cent, down from 2.1 per cent.

The threat of a rapid fall in growth for the US economy, coupled with rising unemployment, spurred the US House of Representatives to vote overwhelmingly last night for a $146 billion economic aid package that would speed rebates of $600-$1,200 to most taxpayers.

The Bill, which came from a compromise between the White House and bipartisan leaders in the House, now moves to the Senate, where modifications are being considered. Ben Bernanke, Chairman of the Federal Reserve, is also expected to respond to continuing economic woes with another cut to interest rates, the second in eight days. He is under pressure to make a reduction of half a percentage point today, setting the rate at 3 per cent. Interest rates would have fallen by a third in just over a week.

Last Tuesday, the Fed slashed the cost of borrowing by three quarters of a percentage point, the biggest reduction for 26 years. The cut came after stock markets had plunged worldwide amid fears that the US economy – already on the brink of a recession – would drag the rest of the world with it.

Wall Street’s Treasury bond market has already priced in a 50-basis-point cut and Mr Bernanke could face a market slide if a further reduction fails to meet expectations.

Mr Bernanke and his rate-setting committee were wrestling with conflicting data about the direction of the economy yesterday. Durable goods data for December leapt by 5.2 per cent – far higher than expected – boosted by export orders for Boeing aircraft, but quarterly results from Countrywide, America’s biggest mortgage lender, signalled a sharp deterioration in the housing sector, as it unveiled a quarterly loss of $420 million (£212 million).

The lender, which collects payments on $1.48 trillion of mortgages, said that more than one in three borrowers with sub-prime home loans was behind on payments at the year-end.

Fourth-quarter gross domestic product data, to be published today, is expected to show that the US economy expanded by an annual rate of 1.4 per cent over the three months.

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