British Prime Minister David Cameron has suffered an embarrassing defeat in parliament over how the referendum he has called on leaving the European Union will be conducted.
The defeat in the House of Commons on Monday was on a technicality, but it highlights the struggle Cameron faces to keep eurosceptic rebels in his own centre-right Conservative Party in line before the vote, due by the end of 2017.
The government had wanted to water down the usual rules on so-called "purdah", under which ministers are banned from making any announcements 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. Thirty-seven Conservatives rebelled against Cameron.
The prime minister wants Britain to remain part of the EU as long as he can secure reforms on issues, such as making it harder for migrants from the bloc to access benefits and dropping the EU's commitment to ever-closer union.
Suspicions are growing among some MPs who oppose the EU 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.
In Monday's vote, eurosceptics teamed up with MPs from the main opposition Labour Party and the Scottish National Party to vote down the move, which they saw as a key test of the government's willingness to address their concerns.
Leading eurosceptic Bernard Jenkin summed up the concerns of many by saying: "Ministers want to use their private offices to organise their speaking tours, they want to use their special advisers who are paid for by the taxpayer to campaign on the referendum. This is not an acceptable use of public money."
Monday's late night sitting was the last day of debate in the Commons on the European Union Referendum Bill, which lays out the rules under which the vote will be conducted.
The bill now goes to the House of Lords, the upper legislative chamber of parliament, for further debate before it can become law.