London: British Prime Minister David Cameron suffered an embarrassing defeat Monday over how the referendum he has called on leaving the European Union will be conducted.  

While the defeat in the House of Commons was on a technicality, it highlights the struggle Cameron faces to keep eurosceptics in his own centre-right Conservative party in line before the vote, due by the end of 2017.

It was Cameron's first defeat in the Commons, where he has a majority of only 16 seats, since winning Britain's general election in May.

The government had wanted to weaken the usual rules on purdah, under which ministers are banned from making any announcements on funding or other issues which could affect the result of the vote for the last 28 days of a referendum or election campaign.

But the normal rules will now be applied after the government's plans were defeated by 312 to 285 votes.

Eurosceptics teamed up with MPs from the main opposition Labour party and the Scottish National Party to vote down the move.

Cameron wants to remain part of the EU as long as he can secure reforms on issues such as making it harder for EU migrants to access benefits and dropping the EU's commitment to ever-closer union.

Suspicions are growing among some eurosceptic MPs that he will be content to secure cosmetic changes to Britain's relationship with Europe ahead of the vote, rather than the deep-seated changes they want.

Monday is the last day of debate in the Commons on the EU Referendum Bill, which lays out the rules under which the referendum will be conducted.

It will then go to the House of Lords for further debate before it becomes law.