Ed Miliband today admitted the race for Number 10 is 'neck and neck ' as he launched Labour 's election campaign at the Olympic park . The Labour leader used a speech at the top of the Orbit tower overlooking the London 2012 stadium to urge a 'spirit of optimism ' and a belief that 'Britain can do better ' He signalled once again that the NHS will be at the heart of his bid for power , announcing a new cap on the profits private firms can make from the health service . Scroll down for video . Labour leader Ed Miliband used a speech at the top of the Orbit tower overlooking the London 2012 stadium to urge a 'spirit of optimism ' and a belief that 'Britain can do better ' Mr Miliband laid out his pitch for power the morning after his mauling at the hands of Jeremy Paxman in the first TV contest of the campaign . Polls suggested David Cameron secured a narrow victory over his rival , but Labour strategists believe it exposed the Prime Minister 's refusal to go head-to-head in a debate . Mr Miliband sought to counter claims his leadership has been too negative , vowing : Britain can do better than this ' . He told activists gathered at the top of the 114metre sculpture at the heart of the Olympic Park : 'As we go out to fight this election , just remember : . 'They 're the pessimists . We 're the optimists . I know this election is going to be tough . 'Like so many races here during the Olympics , it may come down to the wire . Neck and neck . ' I know our opponents will throw everything they have our way . ' But he insisted that Labour has ' a better plan , a better future ' . Introducing Mr Miliband , deputy leader Harriet Harman said he had 'put us within touching distance of winning this general election ' . Mr Miliband laid out his pitch for power the morning after his mauling at the hands of Jeremy Paxman in the first TV contest of the campaign . Mr Miliband announced a Labour government would act to ensure health services are no longer 'threatened ' by privatisation . Mr Miliband announced a Labour government would act to ensure health services are no longer 'threatened ' by privatisation . But he was forced to defend himself against claims that he was scaremongering by referring to 'privatisation ' when no patients are expected to pay for their treatment up front . Under Labour 's plans , a new profit cap - usually 5 per cent - would be set on outsourced healthcare contracts worth over £500,000 , private companies would be blocked from 'cherry-picking ' lucrative treatments and the NHS would become the 'preferred provider ' for all services . Mr Miliband said of the profit cap : 'We do think it 's right to say , when private sector companies are involved , we do n't get excess profits which is draining money away from the National Health Service . 'Look , I think this is going to be common-sense thing that people will think is the right thing to do . I hope other parties adopt this because it 's the right thing to do for the future of our NHS . ' Mr Miliband set off on his campaign battlebus , urging supporters to be 'optimistic ' for the future . Senior shadow minister Ed Balls , Ivan Lewis , Sadiq Khan , Rachel Reeves , Harriet Harman , Tristram Hunt , Yvette Cooper , Douglas Alexander and Chuka Umunna posed with Mr Miliband outside the bus . On people paying for private healthcare , he added : 'What is the real lesson of the past on this - the lesson before 1997 and a lesson I fear for the future if David Cameron were to get back in ? 'It 's that people end up having the option of either waiting for an unacceptably long time or having to go private - that that becomes the offer on the table for people . 'So I think there is a real fear that that becomes the option for people and you do n't have a health service that is properly serving people so there 's a big choice at this election and a big choice about the health service on the ballot paper . ' Tory Health Secretary Jeremy Hunt said : ‘ If you bankrupt the economy like Labour did last time – then you ’ ll put our NHS at risk . We can only have a strong NHS if we have a strong economy , but Ed Miliband doesn ’ t have an economic plan . ‘ We all know Labour want to ‘ weaponise ’ the NHS but this is another policy from Ed Miliband that looks ill-thought through . It risks higher infection rates , higher waiting times and chaos for our NHS . This incompetence is exactly why Ed Miliband is simply not up to the job . ’
Labour leader tries to recreate the 'spirit of optimism ' of London 1997 . Puts the NHS at heart of his bid for power with new cap on profits . But he is forced to defence claims he is scaremongering on privatisation .