The Deputy Prime Minister, Nick Clegg, has today (8 October 2013) launched an appeal for pro-Europeans and those who have benefitted from EU policy and law to accelerate a campaign to keep the UK in the EU. Ahead of the referendum on the issue of UK membership of the Union – currently scheduled for 2017, but with the real possibility of being brought forward if the House of Commons so votes in coming weeks – pro-Europeans will doubtless be glad of Mr Clegg’s intervention. But what are we to make of this in view of the coalition government’s stance towards the EU? Is it the start of a change of perspective?

The starting point for enquiry is one to which the UK is not habituated by tradition: coalition government. When parties combine to form an administration, this offers the opportunity to move from previously-entrenched positions, by playing the ‘they made me do it’ card either at the outset or in response to what Harold Macmillan famously called ‘events’. But this does not seem likely in the present case: Tory backbenchers would not forgive it, and there has not (yet) been a game-changing event in EU or global politics to be woven into a justificatory narrative by pro-EU members of the Conservative Party.

The fact that today’s big announcement came from the Deputy PM, not the Europe Minister, is interesting. Politicians of stature and ability have held this latter post in the past, and the track record of the incumbent, the Conservative MP David Lidington, is blameless. On the other hand, his is not the most active Ministry in government: his website – which I checked this afternoon– sets out a grand total of two policies in the eight months since February this year. So if we want to find out why Mr Clegg’s announcement came today, perhaps we should not expect to find a trail of crumbs that leads back to Mr Lidington’s door.

So what about the Foreign Secretary? William Hague is a respected, heavyweight politician, and hierarchically senior to Mr Lidington. The current Review of Competences – the task of deciding what the UK should seek to repatriate from Brussels, if anything – is largely under his oversight. But he is not known for taking a pro-European line, having run a general election campaign from an explicitly Euro-sceptic position when he led his party; it is hard to see his imprimatur on Mr Clegg’s speech. In addition, although historically the Foreign Office has been a very pro-EU part of the UK government, it is hard to envisage Mr Hague going native. Still less can this be imagined for the Treasury and Home Office – the other two key Ministries with regard to controversial EU issues.

So, it is entirely possible that the DPM’s statement will not even alter the mood music of HMG as such, regardless of what it indicates for Mr Clegg’s own party. But it is an interesting development because in all likelihood Mr Clegg will have briefed on – or even cleared? – his intervention with David Cameron before going public. And in the context of coalition politics, this may serve Mr Cameron as a useful pressure valve, throwing a bone to pro-Europeans in his party and also as a signal to those watching in Brussels, Berlin and Paris that when the referendum comes, the die may not yet be cast.

Is this in fact an opportunity for the government legitimately to be two-faced, with each party appealing to different sections of the electorate? Could it be that we see in future a government with two de facto policies on the EU, at least as far as a referendum campaign is concerned? Time will tell, but this may prove the most likely explanation of Mr Clegg’s salvo.