DAVID Cameron has finally made a choice and announced that his ministers will be free to campaign on both sides of the referendum on Britain’s membership of the EU. But what sort of choice did he have really? The Prime Minister was caught between Scylla and Charybdis from the start - insist on collective responsibility and he risked a number of high-profile resignations; allow ministers to campaign for either side and he risked exposing the divisions in the Tory party and indeed making them worse. What was he to do?

In the end, the Prime Minister went for the second option and will allow ministers to take a personal position on the EU while remaining part of the government, but it is not necessarily the safest choice. When the Labour leader Jeremy Corbyn allowed a free vote on Syria last year, he was accused of a failure of leadership and has been seriously weakened ever since. Mr Cameron’s circumstances may be different – the EU referendum is a one-off issue and does not involve a parliamentary vote – but a number of Tory grandees have already warned that a campaign in which ministers are free to take sides could weaken the Prime Minister. The danger for the Conservatives is that a yes/no debate could very quickly descend into civil war.

However, the alternative of attempting to force ministers to toe the line was never really a serious option for Mr Cameron. Senior ministers would certainly have resigned from the Cabinet and the Prime Minister would have been left trying to maintain an illusion of unity that would never have been convincing, especially in a party that has been seriously divided over Europe since the 80s. There is also a political precedent for Mr Cameron’s strategy to be found in the European referendum of 1975 when Harold Wilson suspended cabinet responsibility for the duration of the campaign.

Wilson’s calculation then was that some of his ministers would have quit rather than support membership of the EEC, and Mr Cameron’s has reasonably made the same assessment of his ministers and the EU 40 years later. The PM also remains hopeful that he will able to sway some doubters with his renegotiation of the terms of Britain’s membership of the EU and, while the talks on a deal have not been going well so far, there are some positive noises coming from Germany more recently.

The arguments for staying in the EU also remain overwhelmingly convincing. As a member of the EU, Britain can maximise its influence on the issues that matter, including currency and taxation; the EU also has a vital role to play in the face of renewed aggression from Russia. But, in making these arguments, Mr Cameron also needs to demonstrate that he is sensitive to the Scottish dimension of the debate. The SNP have said a No vote in the European referendum could trigger another vote on independence and in the Commons the SNP's leader at Westminster, Angus Robertson, again demanded a guarantee that the people of Scotland would not, in his words, be taken out of the EU against their will. At best, Mr Cameron’s reply, that Scotland had a referendum and that’s the end of it, looks injudicious. At worst, high-handedness from the Prime Minister risks deepening the divides that the EU referendum will surely expose.