Boris Johnson has urged France to step up efforts to stem the flow of migrants crossing the Channel after a boat capsized off the French coast with the loss of 31 lives.
The Prime Minister said the tragic incident showed the operations that have taken place to date “haven’t been enough”.
He said he wanted to work with the French authorities to “demolish” the business model of human traffickers who were “literally getting away with murder”.
French interior minister Gerald Darmanin said the dead included five women and a girl.
He told an impromptu news conference in Calais that the boat which sank had been “very frail”, likening it to “a pool you blow up in your garden”.
He said 34 people were believed to be on the boat. Authorities found 31 bodies and two survivors while one person was missing.
An emergency search was sparked when a fishing boat sounded the alarm earlier on Wednesday after spotting several people in the sea off the coast of France.
A rescue operation was under way in the Channel by air and sea as French and British authorities searched for anyone still in the water.
Speaking to broadcasters in Downing Street, Mr Johnson – who chaired a meeting of the Government’s Cobra civil contingencies committee – said he was “shocked, appalled and deeply saddened” by what had happened.
“What this shows is that the gangs who are sending people to sea in these dangerous crafts will literally stop at nothing,” he said.
“But what I’m afraid it also shows is that the operation that is being conducted by our friends on the beaches, supported as you know with £54 million from the UK to help patrol the beaches, the technical support we’ve been giving, they haven’t been enough.
“Our offer is to increase our support but also to work together with our partners on the beaches concerned, on the launching grounds for these boats. That’s something I hope will be acceptable now in view of what has happened.”
He suggested the French government had not always approached the problem in the way the British believed it should.
“We’ve had difficulties persuading some of our partners, particularly the French, to do things in a way that we think the situation deserves,” he said.
“I understand the difficulties that all countries face, but what we want now is to do more together – and that’s the offer we are making.”
Mr Darmanin, who hurried to the French coast as the scale of the incident became apparent, said four suspected people traffickers had been arrested in connection with the sinking.
He said two have already appeared in court and that the regional prosecutor had opened an investigation into aggravated manslaughter.
Mr Darmanin insisted the French authorities wanted to work with the UK to tackle the issue.
After speaking to Home Secretary Priti Patel earlier this week, he said he had sent a list of further assistance they required.
“We have to work together. Sadly our differences with legislation sometimes mean there is a slight lack of co-operation,” he said.
Ultimately it required a tough co-ordinated international response if they were to be effective, Mr Darmanin said.
“This can only be done if Belgium, Germany, Holland, the UK, work all together. Possibly we are not working together enough yet,” he said.
“We really must fight against these criminals just as we fight against terrorism.”