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Britain's notice to leave the EU should not be withdrawn due to Brexit campaign Vote Leave's overspending, Labour and the Tories have said.

The calls come despite almost 200,000 people signing a petition calling for Article 50 to be rescinded.

MPs debated the petition - entitled Rescind Art.50 if Vote Leave has broken Electoral Laws regarding 2016 referendum - in Westminster Hall, but its signatories failed to gain the backing of Labour and Conservative frontbenchers.

A number of revelations in recent months have seen action being taken against members of the official Brexit campaign, Vote Leave, and pro-Leave groups Leave.EU and BeLeave.

However, the size and nature of the sanctions meted out have raised questions about the strength of rules in place to protect democracy.

Shadow Brexit minister Paul Blomfield said it was not possible to credibly say whether "overspending in the region of half a million pounds definitely swung" the referendum result.

And Brexit Minister Chris Heaton-Harris said that while the Government "respects the views and wishes" of those who signed the petition, the referendum result was one that "cannot be ignored".

Mr Blomfield told the debate the Electoral Commission were right to seek much larger fines, but said the law does not provide for overturning referendum results for cheating.

"We have to be guided by the law and while the law provides for that option in relation to parliamentary elections it doesn't provide for that option in relation to referenda," he explained.

"There is a case for a much wider inquiry, but as it stands at the moment the case for overturning the referendum on this basis isn't made.

"Far from strengthening our democracy, disregarding the vote simply on the basis of this issue risks further undermining trust in our political system."

Mr Heaton-Harris, responding to the debate for the Government, added: "There is no question of whether the UK Government will revoke its notification under Article 50.

"It is our clear policy that we will not revoke Article 50 - the people of the United Kingdom gave a clear instruction and the Government is committed to seeing that through."

He said the referendum result reflected not only campaigning but also "considerable and prolonged debate at national and parliamentary level".

"This Government respects the views and wishes of the over 198,000 people who signed this petition but the instruction received from the wider public and their elected Parliament is one that cannot be ignored."