Britain's recession is deeper than thought as official data on Thursday shows the economy shrank 0.3 percent in the first quarter following a higher-than-expected 0.4-percent contraction in late 2011.

The Office for National Statistics said in a statement that British gross domestic product (GDP) shrank 0.3 percent between January and March compared with the final quarter of last year -- confirming its previous reading.

But it revised its data for the fourth quarter of 2011, stating that GDP contracted by 0.4 percent between October and December, worse than a previous estimate of minus 0.3 percent.

A recession is defined as two quarters running of contraction.