David Cameron has admitted that the result of the general election is on a knife edge as he delivered one of his fiercest, most personal attacks yet on Labour leader Ed Miliband.  Launching the Conservative election campaign at the party’s spring conference in Manchester on Saturday, the prime minister sought to focus minds on the choice for voters on 7 May as he tore into Miliband as too weak to run the country, and the party he leads as a “bunch of hypocritical, holier-than-thou, hopeless, sneering socialists”.  “The countdown is on,” said Cameron. “Forty days to say this is a knife-edge election and it can only be cut two ways: Conservative or Labour. Britain on the rise or turning the clock back.” He added: “This is a high-stakes, high-risk election.”  Cameron will visit the Queen in Buckingham Palace on Monday to seek the dissolution of parliament and trigger the general election.  Related: Tories and Labour are neck and neck in last poll before parliament is dissolved  Tory MPs had been hoping their party would be comfortably ahead of Labour in the polls by the time the “short campaign” begins. But the latest Opinium survey for the Observer puts the two parties neck and neck. The Tories are on 34% (down two percentage points on last weekend), while Labour is unchanged on 33%, Ukip on 13% (-1), the Lib Dems up one point on 8% and the Greens also up one point on 7%.  Some Conservatives fear overpersonalised attacks on Miliband could backfire, but Cameron refused to pull any punches. “Some might say: ‘Don’t make this personal’, but when it comes to who’s prime minister, the personal is national. The guy who forgot to mention the deficit could be the one in charge of our whole economy. The man who is too weak to stand up to the trade unions at home could be the one facing down our enemies abroad.  “The leader who thinks leadership is climbing aboard the latest bandwagon – he could be the one taking the make-or-break calls in the middle of the night.  The man who is too weak to stand up to the trade unions at home could be the one facing down our enemies abroad  “The truth is that Miliband’s Labour party isn’t about liberating working people; it’s about telling you what to do. The same old condescending, bossy, interfering, we-know-best attitude of the Hampstead socialist down the ages,” he said.  Meanwhile SNP leader Nicola Sturgeon issued a direct challenge to Miliband to pledge that Labour would join forces with the SNP after the general election to lock the Conservatives out of power. Positioning the SNP firmly in traditional Labour territory on the House of Lords, NHS and minimum wage, the leader reiterated her commitment not to put the Tories into government should the nationalists hold the balance of power after 7 May.  “I call on Labour today to match that pledge – to make clear that if Labour and the SNP combined have more seats than the Tories, they will join forces with us in a vote of confidence to lock David Cameron out of Downing Street.”  Speaking to 3,000 delegates in Glasgow, she added: “If Labour fails to make that commitment, the only conclusion people will draw is that Labour would rather have the Tories back in power than work with the SNP. And that will be the final nail in the coffin of Scottish Labour.”  Turning on its head one of Scottish Labour’s key doorstep messages, Sturgeon insisted: “A vote for the SNP is a vote to keep the Tories out.”  On the NHS, Cameron said a Conservative government would ensure patients across England would be given full access to hospital services seven days a week by the end of the parliament in 2020.  But the plan came under immediate attack from doctors’ leaders. Dr Mark Porter, who chairs the British Medical Association council, said the Conservatives had not even committed the funds needed to maintain existing services. “With existing services stretched to breaking point, a majority of hospitals facing crippling budget deficits and frontline staff under extreme pressure, the NHS needs far more than just words to deliver extra care,” he said.  The chief executive of the Nuffield Trust health charity, Nigel Edwards, said that “even if there were significant extra funding available for the NHS, getting the critical mass of specialist staff needed to make seven-day working a reality would be likely to mean closures or mergers of local services, such as emergency surgery or maternity units. Such changes may well be necessary in the interest of the best clinical care. But they will cost money and will require immense political bravery.”  Labour’s campaign vice-chair, Lucy Powell, accused the Conservatives of misleading voters, saying their spending plans would mean “extreme” cuts to the NHS. “On the NHS, David Cameron misled people in 2010 and he’s misleading them again today,” she said.
PM paints stark choice between himself and leader of ‘sneering socialists’, while SNP demands Labour join in pledge to lock Tories out of No 10