Theresa May's Government found in contempt of Parliament for refusing to release full legal advice on Brexit

British Prime Minister Theresa May's government has been found in contempt of parliament for refusing to release its full legal advice on Brexit, underlining the depth of opposition among MPs to her deal on leaving the European Union.

The row threatened to overshadow the start of five days of debate in parliament on May's Brexit deal ahead of a crucial vote on December 11, when MPs will be asked to approve it.

Opposition parties and the small Northern Irish party that props up May's minority government are furious that it only provided an outline of the legal basis for its Brexit deal after parliament voted to be given the full advice.

1 NEWS Europe Correspondent Joy Reid has the latest from London. Source: Breakfast

They put forward a motion, which was backed by 311-293 in a vote overnight, that found ministers in contempt of parliament and ordered the immediate publication of the advice.

"Today's finding of contempt is a badge of shame for this government. It is of huge constitutional and political significance," Keir Starmer, the opposition Labour Party's Brexit spokesman, said after the vote.

"Never before has the House of Commons found ministers in contempt of parliament."

The sanctions ultimately available include suspending an MP, most likely Attorney-General Geoffrey Cox. It was not clear whether the opposition parties would now push for that.

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Such punishment is usually reserved for backbench MPs guilty of individual wrongdoing. In reality, Tuesday's vote was about putting pressure on a weakened government.

So many MPs, from May's own Conservatives as well as from the opposition parties, have spoken out against the deal that the odds look stacked against her winning the December 11 vote.

Cox gave parliament an outline of his legal advice to the government on Monday.

Andrea Leadsom, Leader of the House of Commons, said overnight that this had been a "full and frank exposition", and that releasing the full advice would set a dangerous precedent.

She said the government, which had sought to slow down the process by referring the issue to parliament's committee of privileges, had fulfilled the spirit of the order to publish.

The government said after the vote that it would now publish the full advice.

Britain's Prime Minister Theresa May speaks during a meeting with Japan's Prime Minister Shinzo Abe at the G20 Leader's Summit in Buenos Aires, Argentina. Source: Associated Press