"What many will find most cheering in these numbers is the stonking 0.7% estimate for growth in the production sector," she said.
"That's the strongest quarterly performance for that part of the economy in many years. Hopes of an export-led recovery are not dashed yet."
Other analysts were also optimistic, despite the growth figure coming in below expectations.
Howard Archer, chief economist at IHS Global Insight, argued that the lower-than-expected growth figure was "not in itself overly worrying".
"Overall growth in the first quarter was clearly dragged down appreciably by the very bad weather in January, and most indicators suggest that there has been a marked pick up in activity since then," he said.
"Furthermore, there must be a very good chance that first quarter GDP growth will be revised up in future releases as more data for March become available and show improved activity."
What is GDP?
The ONS will release two further estimates for growth in the first quarter, based on more detailed economic information not yet available.
But Trevor Williams, chief economist at Lloyds TSB, warned that the growth could equally be revised lower.
"The economy is still recovering," he told the BBC.
"The declines of 2008 are still having an impact [and] the recovery will remain rather weak and could disappoint."
The Institute of Directors, which represents business leaders, also said it expected the recovery in the economy to "look much more L than V-shaped".
The British Chambers of Commerce added that the new figures underlined the challenges still facing the economy.
"It is important for policy-makers to focus on ensuring that the recovery continues and a double-dip recession is avoided," said the business group's chief economist David Kern.
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