Leaders: PM's defining speech on EU must serve several agendas WHEN it comes to extolling the benefits of union, Prime Minister David Cameron is seldom short of words when countering the demands of the SNP to break away from the UK. But when it comes to that other union - the European Union - he is now faced with one of the most difficult speeches he has made as Prime Minister. Whenever he makes this much-delayed speech, he needs to pick his words with the greatest of care. For most of the past 20 years, the issue of Europe has threatened to break the Conservative Party. It is deeply divided. Many backbenchers - and some within the Cabinet - would like to see a radical renegotiation of our terms of membership and the repatriation of powers from Brussels to Westminster. This is the central concern of the Fresh Start group of Conservative MPs. It is set to call this week for the repatriation of more than 130 powers that it claims are vital to retain "national democratic accountability." Outside of the Conservative Party, but drawing a growing number of former Conservative supporters towards it, is the UK Independence Party, campaigning for outright withdrawal from the EU. In recent by-elections it has dislodged the Liberal Democrats from their customary third place. Euro scepticism has never been as strong in Scotland as in the rest of the EU. Indeed, until recently, the SNP was a forceful advocate of our membership of the European single currency. But in some respects the rhetoric of critics of the current terms of membership of the EU - and certainly the emotion - is not dissimilar: both, after all, are fired by a concern over sovereignty. Mr Cameron's pending address on our future relationship with Europe is set to be a defining moment of his premiership. He is likely to hold out the prospect of a renegotiation of our terms of membership to begin after the 2015 general election. This renegotiation would be followed by a referendum likely to offer a choice between approval of the amended terms and leaving the EU altogether. For all the tough-sounding words Mr Cameron will deploy in seeking to hold his party together, a complete break is not at all what he wishes - and indeed would regard as a deeply damaging outcome. To avoid this he needs to advance a positive case for our continued membership of the EU while seeking substantive changes in our terms of membership - a stance supported by the British Chambers of Commerce and business leaders frustrated by ever-encroaching regulation. Other EU leaders have made clear their reservations over granting special concessions to the UK. While it is clear that there is growing unease in the UK over the EU agenda of "ever closer union," the Prime Minister needs to find a position and a positive rhetoric that both persuades the rest of the EU of his case and keeps the UK as a contributing and supportive member, while championing the case for change. Make Glasgow Games smiles better Do you have what it takes to be Glasgow Commonwealth Games volunteer? Are you ready to dress as a giant thistle? Can you stay smiling in a downpour, approach strangers with a silver-tongued: "Can I help you?" radiate good humour at all times and know immediately the answer to the question: "Where is Saucy Hall Street?" If so, waste no time applying. Some 50,000 people world-wide have already registered interest, inspired by the global praise for the 70,000 purple-clad Olympics "games makers" who transformed the atmosphere in London during the 2012 Olympics. Few imagined that the London Games volunteers would make the huge global impact that they did. But in fact their contribution became one of the most remarked upon and remembered features of 2012, drawing admiration and praise from sporting punters to politicians. Their example has now inspired thousands to follow suit and put their names forward to make a contribution to the success of the 2014 sporting occasion, not only within the Commonwealth but around the world. Glasgow starts with the advantage of being a friendly city. And it has every ability to make this a winning feature of the 2014 games. It is not just that volunteers can help visitors who are lost and need guidance to cope with an environment they do not know, but they can also be a wonderful advertisement for Scotland as a tourist destination, encouraging many to consider a repeat visit in future years. Tourist Scotland depends greatly on repeat visitor business, so going that extra smile for the Commonwealth Games could repay itself many times over in years to come.