Sticking to the script on Europe Since Britain's last referendum on its membership of the then European Economic Community in 1975, most mainstream politicians have accepted the question of the country's participation as settled. Britain might be a reluctant partner in Brussels, often striving to slow or soften moves towards further integration, and seeking opt-outs when it is unable to apply the brakes. But the country's continued membership was broadly a given - at least until now. Galvanised by recent electoral losses to the anti-Brussels UK Independence party, opinion within parts of Britain's governing Conservative party has hardened. This goes beyond the mutterings of the usual backbench malcontents. A number of senior veteran Tories, including the former chancellor, Lord Lawson, have come out openly in favour of exit. Up to a third of Conservative MPs are now said to want Britain to leave. Some of this, of course, has to do with low domestic politics. Anxious about their chances of winning a majority at the next election, Tories fret endlessly about Ukip peeling away their more eurosceptic supporters. But it is also a reaction to the way the crisis is changing EU institutions. Europe's response to the eurozone's near meltdown may have been faltering, but it has stripped away the idea that the union has reached a high water mark of integration. Faced with the possibility of the single currency's collapse, the case for more integrated economic government has become received wisdom. The worry is that this could create a new tight core that the UK would never want to join, and which might ultimately exert a dominant influence over the single market. Britain could become a marginalised second-class member, doomed always to be outvoted by the eurozone bloc. David Cameron set out his proposed solution this year. The prime minister insisted that the price of deeper integration be an as yet unspecified loosening of ties between Britain and its EU partners. He has undertaken to renegotiate the terms of the UK's engagement and put the resulting deal to the British people in a referendum after the next election. This newspaper has always argued in favour of UK membership of the EU and we continue to believe that it is in the national interest. Our reasons go beyond a purely economic calculation of cost and benefit and have to do with Britain's place in the world. Membership gives influence over the biggest global market. It helps to keep the US relationship special, and amplifies Britain's sway in a world where economic power is shifting east. Turning inward and away from our nearest neighbours would be no way to win Mr Cameron's global race. Nonetheless, we recognise that today's EU is vastly different to the one that the UK joined in 1973 or indeed the one Britons voted to stay in when they were last offered a say two years later. There is a case for Mr Cameron - or a future government - codifying the relationship between the UK and a new bloc centred on the euro and seeking safeguards for the single market. This could be put to the electorate. But that should only happen when the terms of the eurozone's integration are clear. So how should Mr Cameron respond to the clamour from within his own party? There are some things he should definitely not do. He should avoid, for instance, raising false hopes about what can be achieved in a negotiation with Britain's EU partners to counter those, such as Lord Lawson, who claim the whole exercise is inconsequential. Confusing the protection of existing rights with the repatriation of powers would be a trap. Britain's EU partners will never agree to allow the UK to participate in the single market without accepting its fundamental rules and principles. Pursuing such a course would inevitably push Britain towards the exit. Mr Cameron should stick to his own script. He should lead in the EU, as Margaret Thatcher did on the single market and enlargement. He should also seek allies. One cause the prime minister could usefully adopt would be further liberalisation of the EU's market in services. This is a huge interest for Britain, given its large and dynamic service sector. It is also one where London has a large group of allies, from the Netherlands to Poland and Spain. Above all, Mr Cameron should not fall prey to introspection. He should remember that in his dealings with Europe, he must speak for country not party. Having staked out his policy, he should hold his nerve.