09/06/2015 20:27 BST | Updated 09/06/2016 06:12 BST

PM Faces Brexit Campaign Pressure

David Cameron is facing growing demands to allow ministers to campaign for an EU exit as legislation for an historic referendum cleared its first parliamentary hurdle.

As the Prime Minister prepares for another round of whirlwind diplomacy pushing his renegotiation agenda in Brussels, Boris Johnson insisted dropping collective responsibility in the run-up to the poll would be "safer and more harmonious".

The intervention by the mayor of London, a member of the Prime Minister's political Cabinet, frustrated Downing Street's efforts to move on from yesterday's confusion over whether Mr Cameron had indicated he would sack anyone who defied the government line.

But the European Union Referendum Bill easily passed its second reading in the Commons, by 544 to 53. And an SNP wrecking amendment - calling for 16 and 17-year-olds to be allowed to take part and requiring majorities in each of the four UK nations before 'Brexit' occurs - was also seen off by a majority of 279.

The Bill will now undergo detailed committee stage scrutiny on the floor of the House, starting next week.

Asked if ministers should be allowed to campaign for Britain to leave the EU and keep their posts, Mr Johnson said: "I don't see why not myself."

He added: "I think, probably, it would be safer and more harmonious just to say 'OK, you make your minds up'. I think, on something like this, do you really need to bind everybody in?"

He said that if Mr Cameron got the deal he wanted in Europe, "the overwhelming majority of his colleagues - on both the front and the back benches - will support him".

Mr Cameron has vowed to renegotiate the UK's relationship with Brussels before an in/out vote by the end of 2017.

Mr Johnson left the door open to campaigning for Brexit if the Prime Minister did not achieve an acceptable outcome in his talks with EU leaders, saying: "Let's see where we get to."

He suggested that, unless there was treaty change to make amendments to benefits rules for European migrants demanded by Mr Cameron, the Prime Minister would be forced to recommend a No vote in the referendum.

Mr Johnson said it was clear that "unless we can get treaty change to prevent migrant workers from being able to access benefits before they have been here for four years, there will be no alternative but to recommend a No".

At the weekly Cabinet meeting Mr Cameron "reiterated his position on the approach to renegotiation and the referendum", Downing Street said.

The Prime Minister's spokeswoman said: "The position is very clear. All the Government are behind engaging with our European partners to renegotiate the UK's relationship.

"The decision on the approach during the referendum is for further down the road."

Asked about Mr Johnson's comments, she said: "The Prime Minister is clear that he thinks the approach during the referendum is an issue for further down the road, we need to take this step by step, the focus very much now is on renegotiating our relationship and addressing the concerns of the British people."

Eurosceptics, including former Cabinet minister Owen Paterson, have claimed the Government could try to "fix" the referendum by scrapping the usual purdah restrictions preventing the publication of promotional material by Whitehall before a poll.

Number 10 defended the position, saying Mr Cameron had been clear that "the Government is not going to be neutral on this".

Challenged about the move in the Commons, the Foreign Secretary said there were "operational and political" reasons for lifting the restrictions but insisted that the Government did not plan to "spend large sums of public money" campaigning.

If the restrictions were not lifted they "would stop the Government from 'publishing' material which deals with 'any issue raised by' the referendum question", Mr Hammond told MPs.

"In the context of this referendum that is unworkable and inappropriate", he said, adding that Government ministers would want to campaign without "being constrained by fears" over whether writing a comment on Twitter would breach the law. 

Tory Eurosceptic Peter Bone questioned him, stating that "a lot of people are concerned that the Government will use the apparatus of state to push a case rather than letting the two sides have equal and fair access".

But Mr Hammond insisted that the Government would exercise "proper restraint to ensure a balanced debate" and insisted there was no intention of "spending public money to deliver doorstep mail shots in the last four weeks of the campaign".

Mr Paterson claimed the Government plans would allow taxpayers' money to be spent on a "deluge of propaganda" during the referendum campaign which could leave the public with a sense the vote is "rigged".

After his regular PMQs sessions in the Commons tomorrow, Mr Cameron will attend the EU-CELAC meeting of European, Latin American and Caribbean nations in Brussels.

The Prime Minister is expected to have talks with Cypriot president Nicos Anastasiades tomorrow, followed on Thursday by meetings with Belgian prime minister Charles Michel, Spanish counterpart Mariano Rajoy, Finland's Juha Sipila and Romanian president Klaus Iohannis.

The Prime Minister's spokeswoman said: "This is part of the PM's ongoing approach to talk each leader through why he thinks this is the right approach and the concerns of the British people that he wants to seek to address during the renegotiation.

"His intention is to speak to all of them before the June European council."