The UK needs to consider changes to asylum laws to deter migrants from crossing the English Channel, Boris Johnson has said.
The prime minister said it was currently “very, very difficult” to legally return people who arrive in the UK from France using small boats.
More than 4,000 people have successfully crossed English Channel this way so far this year.
It comes as a group of Tory MPs has called for tougher action on crossings.
Speaking on Monday, Mr Johnson pledged to work with the French authorities to discourage people from making the “dangerous” journey across the channel.
But he added the UK also needed to look at “the panoply of laws that an illegal immigrant has at his or her disposal that allow them to stay here”.
‘Range of options’
On Monday, the Ministry of Defence said it had sent an RAF Atlas transport aircraft to help Border Force spot small boats trying to cross the Channel.
The Home Office had asked defence chiefs for help to deal with migrants making the crossing.
Downing Street said Border Force was looking at a “range of options,” including new measures, to stop boats entering British waters.
The UK is currently following EU asylum law during its 11-month post-Brexit transition period following its departure from the bloc in January.
This includes the so-called Dublin regulation, which states that a person’s asylum claim can be transferred to the first member state they entered.
The PM’s spokesman said the UK wanted to replace the “inflexible and rigid” regulation with a new agreement on returns after December.
He added that the current Dublin rules, which put a time limit on transfers, could be “abused by both migrants and their lawyers to frustrate the returns of those who have no right to be here”.
In a letter to Home Secretary Priti Patel, 23 Tory MPs and two peers said the UK should refuse to sign up to a “similar agreement” to Dublin after December.
They also urged “stronger enforcement efforts” to address a “surge in illegal immigration”.
The group says ministers should do “whatever it takes” to address the rising number of people trying to enter the UK via the English Channel.
“It is strikingly clear that, rather than a ‘hostile environment’, invading migrants have been welcomed,” they wrote.
They added that some migrants had been offered “immediate access to regular payments whilst accommodated at taxpayer expense in expensive hotels.”
“All this is relayed to people smugglers and potential economic migrants in France, encouraging and emboldening those intent on facilitating further border crossings.”
Since the demolition of the infamous ‘Jungle’ nearly four years ago, French authorities have been successful in stopping other large-scale camps from forming.
But migrants do still arrive in Calais; they are just more scattered.
Greater security measures – including a wall built along the motorway with UK funding – have made it more difficult for migrants to stow away on lorries.
But that’s led the people smugglers to increasingly turn to using the equally risky method of small boats.
The UK and France have worked closely on this for close to two decades.
The Treaty of Le Touquet which effectively ‘moved’ the UK border to Calais (and the French border to Dover) to allow checks to happen before crossings, was signed in 2003.
But they can’t change geography.
Calais remains a magnet because it is only 20 miles from the UK – on a clear day in Dover, you can see the headlights of French traffic on the other side of the sea.
No amount of planes, walls or Navy deployments can alter that.
Quite apart from the humanitarian issue here, there is added political pressure for the UK government.
David Cameron was pretty roundly criticised for suggesting in 2016 that Brexit would mean the French would pull out of bilateral agreements and we’d see “Jungles” popping up on the South coast of England.
There’s certainly no indication of that, but there’s no doubt that the images of dinghies landing on Kent’s beaches will be a difficult one for a government that has set huge store by its promise to ‘take back control’ of immigration.
Speaking earlier during a visit to Dover, Ms Patel said the number of recent boat crossings was “totally unacceptable”.
“Collectively with the French, we need make this route unviable,” she added.
Immigration minister Chris Philp is due to go to Paris on Tuesday to demand stronger measures from French authorities.
David Miliband, president of the International Rescue Committee charity, urged politicians not to treat those arriving in the UK as “battering rams” in arguments over immigration.
Speaking on Times Radio, the former Labour foreign secretary said the UK government’s appeal to France to do more to stop boats showed the limits of its rhetoric on “taking back control” of borders.
He said asylum claims needed to be processed much more quickly, saying too many cases were taking more than six months when in Germany the standard waiting time was eight to nine weeks.
On reports the Royal Navy could be used to escort boats back, he urged the UK to work with France rather than taking “unilateral” action.
“The law of the sea saying anyone who is in distress needs to be picked up is there for a reason. Cooler heads need to prevail if the UK is to sustain an effective response as well as a humane one”.