A union representing French police officers has sunk the United Kingdom's latest plan to slow the flow of illegal immigrants across the English Channel.

London had hoped French police officers would soon start intercepting people-smugglers' boats as they left France.

However, France's largest police union, Alliance Police Nationale, has said such interventions, which were to have included inflatable boats being rendered unusable through the jamming of their propellers, would be too dangerous.

"People don't seem to realize how dangerous it is to try and carry out arrests at sea, while trying to force a boat to change course," a source from the union told The Mail newspaper on Sunday.

The union also fears police officers could be held legally responsible if their interventions end in the death or injury of immigrants.

An unnamed source from France's Interior Ministry told The Mail on Sunday: "The police want guarantees that there will be no prosecutions in case of death or injury, but prosecutors say that is impossible. Meetings between lawyers and police chiefs have taken place over the past month, but the judicial authorities remain firm — there will be no waiving of criminal liability if things go wrong."

Funding interventions

The opposition followed lengthy talks between UK Prime Minister Keir Starmer and French President Emmanuel Macron that ended with the two countries agreeing to a deal that called on the UK to send 500 million pounds ($675 million) to France to help fund interventions for the next three years.

Starmer praised the deal in a letter to Macron, in which he said:"It is essential that we deploy these tactics … We do not have an effective deterrent in the (English)Channel."

The plan — which called for police officers to incapacitate vessels suspected of being involved in people-smuggling, even before they had anyone on board — was the latest in a range of initiatives aimed at slowing the number of people entering the UK illegally in order to claim asylum.

Official figures show that, in the year ending June 2025, 49,341 people arrived in the UK irregularly, which was 27 percent up on the previous 12-month period. Some 88 percent of those illegal arrivals entered the UK on small boats via the English Channel.

The UK's previous government had planned to send many of those illegal arrivals to the African nation of Rwanda for processing, with only those deemed genuine refugees likely to be allowed to return to the UK, but that idea was shot down by the courts.

Currently, the authorities in France attempt to stop illegal migrants getting onto boats but, once they are on board, they are not touched until they are intercepted in the open seas and taken to the UK for processing.