The gross domestic product, the broadest measure of an economy's value, rose 0.4 percent compared to the first quarter a year earlier "and therefore has been broadly flat over the last 18 months," the statistics agency said.
The numbers are better than expected and better than the 0.3 percent contraction from the fourth quarter of 2012. If they remain positive in revisions, the growth will mean Britain has avoided an unprecedented triple-dip recession, The New York Times reported.
"Today's figures are an encouraging sign the economy is healing. Despite a tough economic backdrop, we are making progress," Chancellor of the Exchequer George Osbourne said.
Market analyst Nawaz Ali at Western Union Business Solutions called the data "surprising and bullish."
"Doubts about the British economy's performance over the coming quarters will remain. However, the positive figures end the triple-dip threat and will certainly ease pressure on the Bank of England to shift course on quantitative easing, which has been a big worry for currency investors," he said.
Thursday's figures are considered a preliminary estimate, the ONS said, meaning they will be revised, as necessary, as more data become available.
The ONS said the preliminary report is based on 44 percent of the data that go into the final estimate.
The preliminary data also include solid data from the first two months of the year and some March data that are also subject to a revision.
In the preliminary figure, the largest contributor to growth in the first quarter was the service sector, which expanded 0.6 percent January through March, ONS said.
Services accounted for about a half point -- 0.45 of a percentage point -- of the overall 0.3 percent increase.
Industrial production also made a positive index, "largely due to mining and quarrying, which increased 3.2 percent following a week fourth quarter of 2012 when extended maintenance in the North Sea reduced output," ONS said.
Mining and quarrying in Britain includes its vital oil offshore oil production.
Construction was a 0.17 percentage point drag on the overall GDP with construction output off 2.5 percent from the previous quarter, ONS said.
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