Chancellor George Osborne has defended the so-called 'scare tactics' employed by the Remain camp to convince Britain to vote to stay in the European Union.
Speaking to ITV News Mr Osborne said that "the British people want the facts" adding: "There is an overwhelming view from those around the world...which is we would be worse off outside the EU and stronger, better off inside the EU."
Manchester was full of politicians on the first day of the EU referendum campaign including Brexit advocate Boris Johnson who said that the NHS would prosper from money spent in Brussels.
Meanwhile, the Stronger In campaign stuck its message on the economy saying that if that suffered, so would the health service.
Across the UK, with 10 weeks to go, the clock is ticking on Britain's EU membership.
ITV News Deputy Political Editor Chris Ship reports:
Vote Leave campaigner Boris Johnson likened staying in the EU as being "locked in the back of a minicab driven by someone with a wonky satnav".
In his rallying speech in Manchester, he warned that the June 23 referendum was the "last chance" voters will have to decide about the UK's relationship with the EU.
We should be in no doubt that this is the last chance many of us will have in our lifetimes to assert that principle in our relations with the EU. It is called democracy.
Because it is now or never and if we fail to make the change now we will continue to be passengers locked in the back of a minicab driven by someone with a wonky satnav who does not have a perfect command of English and taken to a destination that we frankly don't want to go and I think the people of this country have no idea how far the EU now invades every area of our lives.
Remain campaigners who say the EU is not perfect but there is no alternative are the "Gerald Ratners" of modern politics, he added.
He said: "They keep saying that they are Eurosceptics, but we have no choice, we agree with you about the democratic problem, they say - but it's the price we have to pay."
Boris Johnson, who announced he is backing the Vote Leave campaign in the EU referendum, is making a speech on the first day of campaigning in Manchester.
Watch his speech live at the Old Granada Studios, Manchester:
- The live broadcast has now ended.
The Leave and Remain EU camps have been putting forward their counter-arguments ahead of the EU referendum but how divided is opinion across Britain?
ITV News' Correspondent Martin Geissler has travelled from Lowestoft in England to Londonderry in Northern Ireland to get a snapshot of the public's view on the debate.
Justice Secretary Michael Gove, a key figure in the referendum's Vote Leave campaign said that money sent to Brussels could be better spent on the NHS.
Speaking after Vote Leave launched its advert in Manchester claiming that £350 million, £50 million a day, is handed to Brussels, he said:
At the moment the money that we give to the European Union is spent by others, people we have never elected, never chosen and can't remove.
If that money is taken back, then that £50 million a day will be spent on British people's priorities and the NHS of course is top of people's list.
The £350 million figure has been disputed by other sources that claim it does not take account of the UK's agreed rebate.
Boris Johnson has criticised Barack Obama who plans to urge the UK to remain in the EU referendum branding it "hypocritical".Read the full story ›
Barack Obama has been the "most anti-British" US president in history, Ukip leader and vocal Eurosceptic Nigel Farage has said.
Mr Farage, a leading campaigner for the UK to leave the EU, also voiced his willingness to "work with anybody" on the 'Leave' side of the debate.
He hit back at the president after US officials suggested Mr Obama believed Britain was better off remaining within the union.
Speaking as he handed over a letter to Downing Street protesting the government's £9.3 million pro-EU leafleting drive, Mr Farage said:
Mercifully, this American president, who is the most anti-British American president there has ever been, won't be in office for much longer, and I hope will be replaced by somebody rather more sensible when it comes to trading relationships with this country.
He said the government's leaflets contained "false assertions", adding: "If Mr Cameron is so confident of what's in this leaflet, I will debate it with him, head-to-head, any place, any time, anywhere. Every country in the world has access to the single market, the truth is Britain has a rotten deal."
The first Vote Leave billboard of the referendum campaign has been unveiled in Manchester.
The advert by Vote Leave - named as the official pro-exit campaign - suggests that should Britain vote itself out of the EU, the country's purported £350 million-a-week payment could be better spent on the NHS.
Other sources have disputed this figure, as it does not take account of the UK's agreed rebate.
Vote Leave board member Graham Stringer said the UK could better spend its budget on home-based priorities.
Our NHS is struggling to cope with rising demand and needs the support that is currently siphoned off to Brussels.
If we take back control of our borders, democracy and economy on on 23 June we can ensure that the UK and our health service prospers for this and future generations.
Former Labour MP Alistair Darling has set out what he called the "strong economic case" for Britain remaining in the EU - accusing Brexit campaigners of offering a "fantasy future".
Speaking as the official campaigns both for and against Britain's continued membership of the European Union kick off, Mr Darling said nobody had "any idea" what life outside the EU would look like.
Mr Darling - one of the leading campaigners for Scotland to stay in the UK ahead of its independence referendum in 2014 - said Eurosceptic campaigners had no evidence to back up their claims, and said they were resorting to "attacking the messenger, not the message" as a result.
"Simply abusing your opponents won't get you anywhere," he said.
The EU buys almost half of UK exports, he said, with more than three million jobs linked to UK-EU trade. An estimated 950,000 would be lost by 2020 if the UK leaves the union, he added.
"The benefits outweigh the costs," he added.
The EU referendum will be held on June 23.