For several months, 9.30am on January 23 has been marked down as the moment when Britain would pass officially into recession. Listeners were duly prepared when Gordon Brown popped up for a radio interview after the 8am news to promise the country that he would fight the downturn with every weapon at his disposal.

But a surprise was waiting from the Office for National Statistics (ONS), whose very title conveys a lack of excitement. Its quarterly growth figures suggested that the recession will be longer and deeper than feared.

The economy’s output fell by 1.5 per cent in the final three months of 2008, after a 0.6 per cent drop in the previous quarter. Two consecutive quarters of negative growth add up to a recession in anyone’s language, and Britain is now in the grip of its sharpest for three decades. Fears of a deeper downturn are growing, with some forecasters talking of the most vicious crisis since the Second World War. What was expected to be a formal announcement prompted yet another spate of adverse reaction in what President Obama called on Tuesday a “winter of hardship”.

The steepest quarterly decline since 1980, and a 1.8 per cent fall on the same quarter a year ago, sent the pound to a 23-year low against the dollar, and the FTSE index tumbling below 4,000. Manufacturing contracted by 4.6 per cent, despite hopes that the weak pound would help exporters. Apart from agriculture, all parts of the economy shrank. A leading economist said: “It’s going to be horrible.”

Far worse for Mr Brown, there was something approaching a consensus that the downturn would now stretch into 2010, election year. Alistair Darling, already resigned to having to use the Budget to revise the growth forecasts that were made in the PreBudget Report in late November, declined conspicuously to repeat his prediction of recovery later this year.

Yesterday’s figures gave material aplenty for the doom-mongers. Experts were not prepared to let a rise in December’s retail sales upset the mood of pessimism. They should be “taken with a pinch of salt”, they said.

The ONS figures make a grim litany. Industry as a whole, including utilities companies, sank by 3.9 per cent in the sharpest drop since 1980. The sprawling services sector, accounting for three quarters of the economy, suffered a 1 per cent decline, contracting at the fastest pace since 1979 when Margaret Thatcher came to power.

A rising number of experts expect the economy to shrink by more than 2 per cent this year, with some foreseeing a slump of as much as 2.7 per cent or more. Unemployment is expected to soar, after already registering increases of more than 161,000 in the past two months alone. In the latest stark projections from the City, in a poll by Reuters this week, the jobless total was tipped to rise to as much as three million by early next year.

The housing slump is also expected to deepen, while for those who keep their jobs a stark new era of pay cuts and freezes lies ahead.

However, many experts still believe that the combination of interest rate cuts, the Government’s tax and spending measures, and moves to restore bank lending will eventually lead to recovery. With an election in mind, for Mr Brown and David Cameron the big question from yesterday is how long that will be delayed.

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