LONDON (Reuters) - British Prime Minister Gordon Brown, lagging in opinion polls, said yesterday he wished he had done more to impose better regulation earlier and took full responsibility for his role in the economic crisis.

In an interview with the Guardian newspaper, Brown did not rule out a further economic stimulus in April's budget and said the pure free-market era was over.

Brown, finance minister for a decade under Tony Blair until he became prime minister in 2007, has faced repeated calls from the media and opposition politicians to apologise for not seeing the economic downturn earlier.

"I take full responsibility for all my actions," he said. "But I think we're dealing with a bigger problem that is global in nature, as well as national," he told the newspaper, under the headline 'I should have done more to prevent bank crisis'.

The comments echoed Brown's standard line that the economic crisis, which has pushed Britain into recession for the first time since the early 1990s, is not a home-grown phenomenon. Opposition Conservatives called his response inadequate.

"This shows that Gordon Brown doesn't understand the depth of the problems we face," said Conservative finance spokesman George Osborne. "He is neither acknowledging what he himself got wrong nor apologising for his role in the fundamental failure of his whole economic model."

Brown said tougher regulation should have been introduced to regulate financial markets. "Perhaps 10 years ago after the Asian crisis when other countries thought these problems would go away, we should have been tougher."