The "memorandum of understanding" unveiled at the conference is a political document, but could be developed into a legal agreement between two future governments, if both parties win power.

It states: "The United Kingdom will intercept boats which have launched from French shores and entered British territorial waters and will return the persons on board to France.

"France will ordinarily accept these persons, who will be repatriated to their home country in accordance with the law in force in France concerning expulsion."

Under the proposals, illegal migrants who successfully arrive in the UK from France would be immediately detained and deported to their home country, rather than to France, under plans previously outlined by Reform.

Challenged during a news conference over whether the wording "ordinarily" meant some migrants would not be accepted by France, Farage said it was "legalese".

He argued the proposals would mean there was "no incentive" to pay a trafficker to cross the Channel, and "in very, very short order the business model is broken".

Farage said the "historic document" would "stop the boats forever".

Achieving this goal within the first 100 days of a Reform government is one of the party's key pledges.

Last month Emmanuel Macron's government hit out at Reform's proposals to use the Navy to return migrant boats to France, saying the they would violate the country's sovereignty and breach international law.

Opposition parties also branded the plan unworkable.

Labour has pointed to increased cooperation with France as contributing to the number of small boat crossings falling.

This includes extra officers being deployed to French beaches, and more funding to help prevent crossings.

Last year Sir Keir Starmer's government also signed a "one in, one out deal", which allows the UK to send some small boat-arrivals back to France, while agreeing to take the same number of people from France believed to have a legitimate claim to come to the UK.