How will Surbiton's MP vote?

How will Surbiton's MP vote?  The big vote on whether to support an in-or-out (or somewhere in-between) referendum on membership of the EU is to take place after a House of Commons debate on Monday.  The vote is big news despite it only being symbolic, as the decision will not bind the Government into actually holding a referendum.

Ed Davey MP, as a Lib Dem, has always been supportive of the UK membership of the EU.  However, despite their generally pro-EU views, the Lib Dems did promise an in-or-out vote on the UK membership of the EU prior to the last General Election. 

However, the Prime Minister seems to be very much against such a referendum and is instructing his MPs to follow his lead.  Many Conservative MPs have already indicated that they will not vote the way of the PM, although it's thought that the majority will eventually fall in line.  The vast majority of Labour MPs also look likely to vote against the motion. 

So what will Surbiton's MP do?  Will he vote to keep the Lib Dem pre-election promise?  Or will he fall in line with the PM David Cameron and the Lib Dem leader, Nick Clegg?

I guess that like most people, I don't really take a close interest in the voting patterns of my MP unless it's on a big issue.  The last time this happened was when Ed Davey voted to increase student fees in December 2010.  There was an awful lot of pressure on him not to vote this way, but he did.  I would have thought that this would suggest he is likely to follow the official Coalition line of voting against the referendum.  We'll have to wait and see.