The figure for the final quarter of 2008 showed the biggest fall in GDP since 1980. Brown said on Friday he was using "every weapon at our disposal" to fight the economic crisis. "But we need the international co-operation as well," he told BBC radio.
Friday's data sent the British pound sliding to a 23-year low versus the dollar and London's FTSE 100 index of top shares to under 4,000 points. The generally-used technical definition of a recession is two quarters running of negative economic growth. Analysts warned of a long journey ahead before the British economy recovered.
"Our current forecast is for UK GDP to contract by 2.9 percent in 2009, with declines in output occurring through all four quarters," said Howard Archer of IHS Global Insight. "This would be the sharpest contraction since World War II. Furthermore, we see GDP only flat overall in 2010 as recovery develops very gradually."
The British economy grew by 0.7 percent in 2008, the slowest annual rate since 1992, the ONS said on Friday. Britain joins the United States, the eurozone and Japan in recession as the global economy struggles to recover from the fallout of the credit crisis.
Germany on Wednesday said it would suffer its worst recession since World War II this year, with half a million more people in Europe's biggest economy expected to lose their jobs. In Britain, the unemployment rate has jumped to a decade-high 6.1 percent with nearly two million out of work as international groups such as Nissan have slashed local jobs and several retailers have collapsed.
Banks have also cut staff as they continue to be bailed out by the government to the tune of billions of pounds. In a bid to stave off a deep recession, the Bank of England (BoE) has slashed British interest rates to an all-time low of 1.5 percent.
However tumbling borrowing costs have deterred foreign investment, severely hurting the pound, which this week also struck an all-time low against the yen and has reached near-parity with the euro. The BoE's monetary policy committee earlier this month voted 8-1 to cut interest rates by half a percentage point to the lowest level since the central bank's formation in 1694.
One policymaker, David Blanchflower, voted in favour of cutting rates by 100 basis points, arguing that it was "becoming increasingly probable that there would be a deep and prolonged recession."
"Our call is still that the committee will bring rates down by a further 0.5 percent to 1.0 percent next month, although the weakness of sterling, which has intensified today (Friday), provides a risk that rates remain on hold at 1.5 percent for a while longer," said Investec Securities analyst Philip Shaw. The BoE's main task is to keep inflation at a government-set target of 2.0 percent.
British 12-month inflation dived in December owing to a tax cut on goods and services, falling energy prices and heavy pre-Christmas discounting, official data showed Tuesday.
The Consumer Prices Index (CPI) annual inflation rate sank to 3.1 percent in December, the lowest level since April 2008, from 4.1 percent in November. The BoE is meanwhile considering increasing money supply to ensure growth at all costs does not slow so much that inflation falls below target.
BoE governor Mervyn King told businessmen Tuesday that the bank was considering the "unconventional measures" that the government placed at its disposal as part of a new rescue package for banks unveiled this week. King stressed the priority was to get banks lending again to help cash-starved businesses and individuals, and said new measures announced this week would help.
The government on Monday unveiled a second multi-billion-pound bank rescue package aimed at kick-starting its stalled economy but financial shares plummeted amid growing fears of deepening recession. Reports suggest the latest bailout - which may boost an ailing housing market - is worth some 200 billion pounds. The news came after Royal Bank of Scotland forecast an annual loss of up to 28 billion pounds - a record in British corporate history - owing to the credit crisis and its part in a costly 2007 take-over of Dutch lender ABN Amro.