WHITEHALL could undertake a Scottish referendum-style publicity drive on the costs of Britain leaving the European Union but only once David Cameron's negotiations with his EU partners has been completed, No 10 has indicated.

The prospect has been raised as the Prime Minister travelled to Berlin for talks on his EU reform plan with German Chancellor Angela Merkel ahead of today's European Council in Brussels, where he also intends to raise it with his EU counterparts.

In the run-up to the independence referendum, several UK Government departments became involved, producing research, publications and private opinion polls, that supported the pro-Union cause and which cost the taxpayer more than £1 million. At the time, the Yes camp denounced the exercise as fear-mongering.

Asked if the PM was considering a similar Whitehall exercise ahead of the EU poll, his spokeswoman replied: "It's one for further down the road; we're focused on the renegotiation at the moment. So we haven't taken firm decisions on how we would approach that."

But she pointed out David Lidington, the Europe Minister, had made clear the Government would need to "look at these sort of issues" and how they were best communicated to voters in the run-up to the key in/out vote.

Downing Street explained that following the first stage of the PM's strategy - talking to his EU counterparts on the broad thrust of his reform plans - the second stage, involving UK Government officials, would begin. This is likely to commence following this week's key European Council in Brussels and last until the year's end. Then, the third stage of Mr Cameron engaging with his EU partners over detail will follow before the referendum; expected in autumn 2016.

Jonathan Faull, a senior British official at the European Commission, has been appointed to head a Brussels task-force relating to the UK referendum and to see "what is possible" in terms of Britain's demands.

At present, Mr Cameron is focusing on four key areas:

*introducing a four-year ban on EU migrants claiming in- work benefits;

*opting out of the bloc's commitment to "an ever closer Union";

*empowering national parliaments to block EU legislation and

*giving more protection to non-eurozone members so they cannot be outvoted on the single market by those within the eurozone.

Ahead of the two-day EU summit, the PM said: "This is my first European Council since the election and it's the first EU summit where renegotiation of the UK's relationship with the EU is formally on the agenda.

"This presents an opportunity to get the negotiation underway and to kick off a process to work through the substance and to find solutions.

"It will take us another step closer to addressing the concerns that the British people have about the EU and closer to changing the status quo for the better and then giving the British people a say on whether the UK should stay in or leave the EU," he added.

But the summit schedule made clear the UK's reform agenda would not be discussed at either of the two planned working sessions, which will focus on migration, jobs, growth, competitiveness and security. Instead, it will be discussed over dinner tonight.

Highlighting how difficult Mr Cameron's task is set to be came from Emmanuel Macron, the French Economy Minister, who warned the PM he could not be allowed a "Europe a la carte".

"I don't understand how it is possible to say 'we the UK have all the positive aspects of Europe but don't want to share any of the risk with any member states'".

He added: "It just doesn't fly. It's a common responsibility."

Meantime, an Irish parliamentary committee issued a report, calling for a way to be found for the UK to remain in the EU; if possible, without treaty change.

Dominic Hannigan, its chairman, said: "The committee's view is that an EU without the UK weakens Ireland and Europe."