The British economy shrank by 0.4% in the three months to the end of September, official figures reveal.
Britain is now in the longest recession since quarterly records began in 1955. It is the first time since then that the country's gross domestic product (GDP) has contracted for six consecutive quarters.
However the figures could still be revised up or down at a later date, because this figure is only the first estimate.
Quarterly growth of 0.2% had been expected in the figures from the Office for National Statistics.
Chancellor of the Exchequer Alistair Darling still expects to see growth by the turn of the year.
"We're coming through the deepest and most profound downturn that we've seen in this country and throughout the world for generations," he told the BBC.
"It was bound to be a slow process but I'm confident that provided we maintain the support we're providing to the economy, to businesses, to people then we will see recovery."
The pound fell sharply after the figures were released, reflecting the fact that many observers had expected the UK to have grown during the quarter.