David Cameron should avoid negotiating with his European partners "through a megaphone" and be ready to make concessions in order to achieve meaningful reform, former Tory prime minister Sir John Major has said.
Sir John's latest intervention comes as Labour accused Cameron of causing the "biggest loss of influence in a generation" due to his stance towards the European Union.
The Tory leader has pledged to try and claw back powers from Brussels and put the renegotiated offer to voters in a referendum by 2017. Cameron has also promised to curb the European founding principle of free movement in a bid to limit the number of migrants coming to Britain, although other European leaders have warned that it is "non-negotiable".
But speaking to the European magazine, Sir John said that the UK needed to "remove the misunderstandings and neuroses that often exist in negotiations" with EU member states.
"I am shocked about the extent of the misunderstanding about the British position on freedom of movement," he said. "If we discuss these issues rather than debate them through a megaphone, then we are likely to achieve agreement."
"There is no such thing as a negotiation that is made without concessions on both sides. If there aren’t concessions on both sides, it isn’t a negotiation – it is an imposition."
John Major has plenty of advice for Cameron on how to succeed in Europe
Europhile business groups endorsed Sir John's message. Lucy Thomas, campaign director of Business for New Europe, told the Huffington Post UK: “John Major is right that the best way to achieve EU reform is to work with our friends and allies, not alienate them with unrealistic demands, or using megaphone diplomacy for short-term political gain.
“It is important to remember that our natural allies in the EU ‘want the UK to remain in, but not at any cost’. Instead, we need to be finding common ground with European partners and as Angela Merkel said on her recent London visit, ‘where there’s a will there’s a way’.”
However, Eurosceptic groups took issue with the former Tory premier's message. Matthew Elliott, chief executive of the pro-EU referendum group Business for Britain, told the HuffPost UK: “The EU is in serious need of reform and cannot afford to shy away from that fact. As a potential referendum approached, the UK needs to be clear on what changes it believes a competitive EU must embrace, whether some in Brussels want to hear it or not.
"Some might decry this as megaphone diplomacy, but with so many past failed attempts to overhaul the way the EU works it’s time the volume was turned up.”
Sir John also expressed measured optimism about Cameron's prospects of changing the rules surrounding European free movement, arguing that if European leaders were actually committed to the EU's founding principles, it would "cut the British argument about Freedom of Movement at the knees".
He said: ""So are we to be told by our European friends that free movement of people is sacrosanct, it is a founding element of the European Union and it cannot even be constrained at a time of emergency, and yet all of the other things we signed up to in 1973 and enshrined in legislation in 1987 cannot be finished."
"Let us do so [honour the EU's founding principles] and it will change the British perception of Europe. Let us have complete Freedom of Movement. Let us complete the Single Market. Let us complete an energy market. Let us complete a digital market. Let us complete a free movement of goods.
"Let us complete a free movement of services. Not only would that spark the most enormous boom to the whole of Europe, but you would also strip away many of the things that cause the British to think: “Is this what we expected when we joined the European Union?”
Meanwhile, Lib Dem business secretary Vince Cable has hit out again at the prime minister's renegotiation efforts, suggesting that he is "deluded". He also warned that the referendum was "dangerous"" because it could hurt investor confidence in Britain.
Labour's shadow foreign secretary Douglas Alexander is also set to attack Cameron's European diplomacy Tuesday, warning that a Conservative re-election would mark a "point of no return' in the UK's relations with its EU partners.
During a trip to Paris, he will say that Labour would "repair and reset" relations with the EU if they win the next election.
Speaking at the headquarters of the French Socialist Party, Alexander is expected to say: "Before David Cameron became prime minister, Britain was at the heart of EU decision-making.
"Yet when he leaves Downing Street in May, he will have presided over the most significant decline in British influence in Europe for a generation.
"During his time in Downing Street David Cameron has done serious damage to Britain's status in Europe and in turn has diminished our standing in the world.
"The re-election of David Cameron could mark a point of no return for Britain's relations with the EU."