Prime Minister David Cameron has admitted that the European Union needs more reform as he laid out the benefits of the UK staying in the EU, after claims the pro-Remain campaign had resorted to project fear.
The Prime Minister said: "I'm the first to say there needs to be further reform of the EU. My renegotiation isn't end of the road for reform; it's another important milestone in Britain and our ongoing mission in making sure the EU works for us."
The comments came as Cameron struck a more positive tone and argued that full access to the EU's internal market helps British firms by reducing trade barriers.
He said that retaining access to the single market enables UK businesses to sell goods to a market of 500m people, without the threat of tariffs, pointing to the car industry, as well as the pharmaceutical and food industries.
"The question isn't whether Britain could still be a great country outside Europe," he said. "Of course it could. The question is: where will our economy be stronger; where will our children have more opportunities."
The Prime Minister also said the fact the UK is in the EU is one of the reasons foreign companies want to invest in Britain, creating jobs and helping finance the UK's current account deficit.
The speech comes after pro-Brexit campaigners, including Boris Johnson, repeatedly slammed Cameron for focussing on the possible risks of leaving the EU in what has been labelled "project fear".
Most recently, Mayor of London Boris Johnson said that British Chambers of Commerce John Longworth's suspension was due to pressure from "agents of project fear".
But Cameron has now said that arguments about the EU should be presented in a "calm and rational way".
Cameron again hit out at the pro-Leave campaign, saying it has failed to outline what would happen after a Brexit scenario.
He said: "If there's one thing lacking in all that they've said so far, it is specifics. What trade relationship would Britain have with Europe?"
"One one side we've got the facts about how the single market, in a reformed European Union, makes us better off. And on the other side, what we have is unanswered questions," he added.
Cameron drew attention to the uncertainty amid criticism that Leave campaigners aren't able to tell voters what deal they would strike with the EU in the event of Brexit.
He also slammed the Leave campaign, stating: "For those who advocate leaving, lost jobs and a dented economy might be collateral damage, or a price worth paying. For me, they're not. They never are."
However, pro-Brexit group Leave.EU hit back, saying it is the Prime Minister who has cost the country jobs.
Leave.EU co-chairman Richard Tice said: "On the contrary: it's the Prime Minister who accepts open borders hundreds of thousands of jobs being destroyed in areas like fishing, steel and the digital sector a price worth paying to stay in this politicians' members' club."