Miliband's NHS Pledge At Campaign Launch
The event in east London came after Mr Miliband and Prime Minister David Cameron answered questions in the Battle For Number 10, the first showdown of the campaign.
Launching the party's push for power in the "tightest general election in a generation", Mr Miliband said: "The Tories say this is as good as it gets.
"We say Britain can and must do better than this."
Referencing the special programme broadcast on Sky News and Channel 4, the Labour leader claimed the PM's performance showed he was "rattled", "running from his record" and "living in a different world".
The election on 7 May is a choice between "two different visions" for Britain, Mr Miliband said.
"A Tory government that looks out only for the few, or a Labour government that will stand up for working families in every part of our country," he claimed.
At the heart of the launch was a promise of a "double lock" to protect the health service.
Mr Miliband said Labour would act to ensure health services are not threatened by privatisation and pledged to provide ¬£2.5bn in extra cash, paid for by taxes on expensive properties and tobacco companies and a crackdown on tax avoidance.
A new profit cap - usually 5% - would be imposed on outsourced healthcare contracts worth more than ¬£500,000, private firms would be prevented from "cherry-picking" lucrative treatments and the NHS would be the "preferred provider" for all services.
Mr Miliband said: "Just think about how far backwards the NHS has gone in the last five years.
"People waiting longer and longer to see a GP. Ambulances queuing up outside¬†hospitals, because A&E is full. Even a treatment tent erected in a hospital car park.
"For all the promises, for all the air-brushed posters, David Cameron has¬†broken his solemn vow to the British people when it comes to our NHS."
He admitted the race for Downing Street would be neck-and-neck and could "come down to the wire".
Mr Miliband said: "I know our opponents will throw everything they have our way, because they're desperate to hang on to power.
"But we know we can win this fight on behalf of the British people."
Scottish Labour leader Jim Murphy has also launched the party's campaign in Glasgow.
Addressing activists, Mr Murphy called on them to help Labour "consign David Cameron and his austerity to the dustbin of history".
In response to Mr Miliband's remarks, Conservative MP and Health Secretary Jeremy Hunt said: "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."