Intervention of the ex

Like being ditched by a former lover, Tony Blair just can't let go of the Labour Party, chipping in regularly while Gordon Brown maintains the silence of a mausoleum.  Now he feels a need to bolster it as it 'suffers' a moderate set of election results as UKIP outperform all the other parties at the European Parliament elections.  Rejecting calls for Labour to promise an In-Out referendum on the EU in the next parliament or at the general election, Blair argued that such a promise hadn't done much to help the Tories.  Of course, the likes of Frank Field are causing mischief - in the manner of their Tory counterparts, they see a referendum merely as a mechanism to leave the EU rather than a genuine interest in the will of the people - and Field himself has also had a very hard line on immigration. 
Blair sees this, knowing if Labour were to triumph on the back of such a referendum promise, they would 'lose' it on an 'In' campaign as people (egged on by ex-David Cameron Tory party) would be inclined to give the government a mid-term kicking.  Referendums are rare when the electorate vote on the issue at hand, rather than a concatenation of side concerns.  The AV electoral reform referendum was transformed into a 'Kick Nick Clegg' opportunity.  In France, Jacque Chirac's government lost the EU Constitution referendum as people wanted to stick it to their political masters.
If the UK were to leave the EU, of course, it would disqualify Blair from ever becoming European president (unless Scotland went its own way and he reactivated his Scottish heritage).  But Blair also has a fondness for European integration that often ran into the buffers of Gordon Brown and the old socialist guard.  He may have once professed a desire to leave the EEC to gain promotion within his party in the 1980s but whereas he is malleable and opportunistic in his views, Europe is close to his heart as was seen when he took apart a UKIP heckler in 2005 when asked why Britain was sending aid to pay for Hungarian drains (basically, as the quality of life improves in Hungary, the more Britain can trade with them - raising the poor raises the rich too).  For Labour to follow the Tories, they might win the (election) campaign but lose the war if Britain left.