Rishi Sunak said today that illegal migrants will overwhelm Britain unless global refugee laws change, as he met Italian Prime Minister Giorgia Meloni in Rome.
The PM warned failing to tackle the issue would 'destroy the public's faith' in politicians and governments.
He was speaking at an event organised by Ms Meloni's right-wing party which has previously been attended by Hungary's Viktor Orban and ex-Trump aide Steve Bannon.
Downing Street said in the days leading up to the summit that Mr Sunak and Ms Meloni were 'likeminded' on immigration.
The pair have appeared close in previous meetings and were again pictured today looking very friendly, as they smiled and shared a warm embrace.
Rishi Sunak said today that illegal migrants will overwhelm Britain unless global refugee laws change, as he met Italian Prime Minister Giorgia Meloni in Rome
Downing Street said in the days leading up to the summit that Mr Sunak and Ms Meloni were 'likeminded' on immigration
The pair have appeared close in previous meetings and were again pictured today looking very friendly, as they smiled and shared a warm embrace
The PM warned failing to tackle the issue would 'destroy the public's faith' in politicians and governments
He was speaking at an event organised by Ms Meloni's right-wing party which has previously been attended by Hungary's Viktor Orban and ex-Trump aide Steve Bannon
Mr Sunak told the gathering of Italian conservatives and right-wingers that 'enemies' want to use migration as a 'weapon' and are 'deliberately driving people to our shores to try to destabilise our society'.
He added: 'If we do not tackle this problem, the numbers will only grow. It will overwhelm our countries and our capacity to help those who actually need our help the most.
'If that requires us to update our laws and lead an international conversation to amend the post-war frameworks around asylum, then we must do that.
'Because if we don't fix this problem now, the boats will keep coming and more lives will be lost at sea.'
He had warm praise for Ms Meloni, at whose Brothers of Italy annual Atreju event he was speaking.
Ms Meloni is another prime minister who has sought to lead tough action on migrants arriving across the Mediterranean, and the two leaders have developed a close partnership in recent months.
Rishi Sunak speaks to Girorgia Meloni during their meeting in the Italian capital today
The pair were all smiles as they greeted each other on stage at the political festival in Rome
The pair, who have appeared close in previous meetings, were seen today holding hands
The pair also met Albania's prime minister Edi Rama for talks on illegal migration
While in Rome on the one-day trip, Mr Sunak also met Ms Meloni and Albania's prime minister Edi Rama for talks on illegal migration.
Billionaire entrepreneur Elon Musk was also present at the Atreju event.
Mr Sunak and Ms Meloni embraced as Mr Sunak prime minister left the stage, to loud applause from the audience.
Touching on their shared admiration of long-serving Conservative prime minister Margaret Thatcher, he said 'I can only guess what first attracted Giorgia to the strong female leader who was prepared to challenge the consensus, take on stale thinking and revive her country both domestically and on the international stage.'
He said that Baroness Thatcher's 'radicalism and drive' had to be applied to the issue of illegal migration, as he warned: 'It is a fundamental tenet of sovereignty that it is us who should decide who comes to our countries and not criminal gangs.
'If we cannot deliver on that, our voters will lose patience with us and the way in which their countries are run and rightly so.'
Number 10 said that after the talks Mr Sunak and Ms Meloni had agreed to co-fund a project that would see the two countries 'promote and assist the voluntary return' of migrants currently stuck in Tunisia.
Tunisia neighbours Italy just across the Mediterranean and attracts many migrants from several African countries who begin their journey to Europe there.
Mr Sunak also stressed the need for schemes like the Rwanda plan, which dominated the agenda at Westminster this week as Mr Sunak sought to win a crunch vote on the legislation.
Some 292 people made the crossing in seven boats on Friday, according to Home Office figures published on Saturday.
It was confirmed a migrant died and another was left in a critical condition during an incident on Friday.
Italian Prime Minister Giorgia Meloni kisses British Prime Minister Rishi Sunak on the cheek
The pair were deep in thought as they appeared at the gathering of right-wing supporters
More than 29,000 people have crossed the English Channel to reach the UK so far this year - more than the same time in 2021, but fewer than last year
Shadow immigration minister Stephen Kinnock said it was 'not too late' for the prime minister to change direction.
He said: 'After a week in which the Prime Minister has failed to convince many of his own backbenchers that he has a workable plan to end dangerous boat crossings, we hit a new grim milestone - far from stopping the boats, on Rishi Sunak's watch this year 600 boats have crossed.
'It's not too late to change direction.
'At the political summit he's attending today in Italy, the Prime Minister should commit to stop wasting time on the Rwanda gimmick and adopt Labour's plan to invest in a cross-border policing unit to crack down on the criminal smuggling gangs making millions in the channel, put stronger powers in place and get a new security agreement including working with Europol so that we can tackle the problem at source.'
The trip to Rome comes as Mr Sunak has sought to win support from European allies to help crack down on illegal migration, with Albania and Italy seen as among the key partners.