Boris Johnson has pledged to clamp down on immigration after Brexit by introducing a points-based system if he becomes prime minister.

The Tory leadership frontrunner said he would bring in an Australian-style system that would judge prospective immigrants on the contribution they could make to the UK.

As the leadership candidates traded promises, his rival, Jeremy Hunt, vowed to scrap the tuition-fee debt of young people who start businesses.

The government has already announced that freedom of movement will end after Brexit and said EU citizens will no longer be given preferential rights to live in the UK. Ministers have proposed a skills-based immigration system and are consulting on how this should work after 2021, when the Brexit transition period would end.

Mr Johnson said he would order the Migration Advisory Committee, which makes recommendations on how the immigration system should work, to look at how the Australian points-based system could be adopted in the UK.

Immigration applications should be assessed on three criteria, he said: the contribution they can make to the UK, through having a firm job offer and the ability to speak English; guarantees that they will not put a strain on public services, suppress wages or take jobs from people already in the UK; and checks to ensure that they are not criminals or a threat to the UK.

Mr Johnson said he would ensure the rights of EU citizens in the UK were guaranteed regardless of the new system that is introduced.

He said: “We will restore democratic control of immigration policy after we leave the EU. We must be much more open to high-skilled immigration such as scientists but we must also assure the public that, as we leave the EU, we have control over the number of unskilled immigrants coming into the country.

“We must be tougher on those who abuse our hospitality. Other countries such as Australia have great systems and we should learn from them.

He added: “We must also ensure that EU nationals’ rights are protected. This should have happened straight after the referendum. I will sort it out immediately and make sure that this issue is properly dealt with and millions of people can stop worrying.”

Speaking at a digital hustings on Wednesday night, with viewers sending in questions via Facebook and Twitter, Mr Johnson said there was not "any other mainstream Tory politician who has been so strongly committed to our society being open talent and open to immigration".

He said: "I do want talented people to be able to come here and I do want the agricultural sector to be able to satisfy their requirements - it's incredibly important - but it's got to be done on the basis of system of democratic control."

He also played down suggestions that he would take Britain out of the EU without an exit agreement, insisting the prospects of a no-deal Brexit were "a million to one against".

The frontrunner to succeed Theresa May has said he will deliver Brexit by 31 October regardless of whether or not a deal is in place.

Biggest lies told by Boris Johnson Show all 5 1 /5 Biggest lies told by Boris Johnson Biggest lies told by Boris Johnson Made-up quote for The Times Johnson was sacked from The Times newspaper in the late 1980s after he fabricated a quote from his godfather, the historian Colin Lucas, for a front-page article about the discovery of Edward II’s Rose Palace. “The trouble was that somewhere in my copy I managed to attribute to Colin the view that Edward II and Piers Gaveston would have been cavorting together in the Rose Palace,” he claimed. Alas, Gaveston was executed 13 years before the palace was built. “It was very nasty,” Mr Johnson added, before attempting to downplay it as nothing more than a schoolboy blunder. PA Biggest lies told by Boris Johnson Sacked from cabinet over cheating lie Michael Howard gave Boris Johnson two new jobs after becoming leader of the Conservatives in 2003 – party vice-chairman and shadow arts minister. He was sacked from both positions in November 2004 after assuring Mr Howard that tabloid reports of his affair with Spectator columnist Petronella Wyatt were false and an “inverted pyramid of piffle”. When the story was found to be true, he refused to resign. PA Biggest lies told by Boris Johnson Broken promise to boss In 1999 Johnson was offered editorship of The Spectator by owner Conrad Black on the condition that he would not stand as an MP while in the post. In 2001 he stood - and was elected - MP for Henley, though Black did allow him to continue as editor despite calling "ineffably duplicitous" PA Biggest lies told by Boris Johnson Misrepresenting the people of Liverpool As editor of The Spectator, he was forced to apologise for an article in the magazine which blamed drunken Liverpool fans for the 1989 Hillsborough disaster and suggested that the people of the city were wallowing in their victim status. “Anyone, journalist or politician, should say sorry to the people of Liverpool – as I do – for misrepresenting what happened at Hillsborough,” he said. PA Biggest lies told by Boris Johnson ‘I didn’t say anything about Turkey’ Johnson claimed in January, that he did not mention Turkey during the EU referendum campaign. In fact, he co-signed a letter stating that “the only way to avoid having common borders with Turkey is to vote Leave and take back control”. The Vote Leave campaign also produced a poster reading: “Turkey (population 76 million) is joining the EU”

He said: "We need to come out of the European Union on October 31 and get it done.

"We need somebody who believes in that project, who has campaigned on that project for many years and who knows how to get a good deal out of Brussels."

He added: "It is absolutely vital that we prepare for a no-deal Brexit if we are going to get a deal.

"I don't think that is where we are going to end up - I think it is a million-to-one against - but it is vital that we prepare."

Mr Johnson and Mr Hunt stepped up their campaigning ahead of a series of hustings on Friday and Saturday, with just over a week to go until Conservative party members receive their ballot papers.

Unveiling his plan to encourage more graduates to start businesses, Mr Hunt said that scrapping tuition-fee debt for business owners would help “turbocharge” the economy.

The foreign secretary has repeatedly emphasised his own experience as an entrepreneur while making his case to be the next prime minister.

Only 1 per cent of university graduates currently go on to start their own business – a figure Mr Hunt said he wanted to increase.

He said he would scrap the tuition-fee debt of anyone who starts a company that ends up employing at least 10 people for five years.

Mr Hunt said: "If we are to turbocharge our economy and take advantage of Brexit, we need to back the young entrepreneurs who take risks and create jobs.”

Boris Johnson pledges to deliver Brexit by 31 October 'do or die'

“I started my own business [and] I still use the lessons that experience taught me – focus, drive and the art of negotiation – every single day.

“I want more young people to have the confidence to take the decision to start their own business, so we create wealth and start thriving as a country again.”

It was unclear how much the pledge would cost, although Mr Hunt’s team said that student entrepreneurs created far more money for the economy than the cost of their tuition fees.