Reform UK has proposed using the Royal Navy to intercept small boats in the English Channel and return the people on board to France or Belgium, escalating the party’s push for a far tougher response to unauthorised crossings into Britain.

The proposal, called Operation Fortress, was set out by Nigel Farage’s party as a future-government policy.

It would deploy Royal Navy offshore patrol vessels and Royal Marines to stop boats at sea, take those on board into custody and escort them back across the Channel.

Reform describes the approach as “rescue and return”, rather than a policy of forcing unsafe vessels back through the water.

The central obstacle is that the policy would depend heavily on French cooperation.

Britain cannot simply land people in France without Paris accepting them, and French officials have described the idea of unilateral returns as unacceptable and unlawful.

Zia Yusuf, Reform’s home affairs spokesman, has argued that France would have to take people back, but that is a political demand rather than an existing agreement.

Legal and maritime experts have also raised concerns about the plan’s practical limits.

Ships have duties to assist people in distress at sea, and small boats crossing the Channel are often overcrowded, unstable and vulnerable to capsizing.

Any attempt to intercept or transfer people from a dinghy would have to prioritise rescue and safety.

A return operation without a formal agreement with France could also trigger disputes over sovereignty, human-rights obligations and responsibility for asylum claims.

The proposal arrives while crossings remain a highly charged issue in British politics.

Official provisional figures recorded 1,176 people arriving in small boats over four days between 28 July and 1 August.

The data do not include people prevented from leaving France or intercepted by French authorities, but they underline the continuing scale and volatility of the route.

The Channel is one of the world’s busiest shipping lanes, and each crossing poses immediate risks to those on board as well as to rescue crews.

On Monday, British and French teams rescued 157 people after a boat’s engine caught fire and the vessel began breaking apart.

French vessels took 103 people to Boulogne-sur-Mer, while British authorities assisted in the operation.

Britain and France already cooperate on patrols, intelligence, surveillance and efforts to prevent departures.

That cooperation is essential to any policy intended to reduce crossings, because most journeys begin from the French coast.

Reform’s proposal would therefore require more than naval assets: it would need a durable bilateral returns arrangement, operational rules and a legal basis accepted by both governments.

Operation Fortress has also appeared during a wider contest on Britain’s political right.

Rupert Lowe, the former Reform MP who now leads Restore Britain, has called for cooperation between the two parties to avoid splitting their support.

Farage has said he is open-minded about discussions, while rejecting conditions attached to Lowe’s offer and disputing aspects of their private contact.

No pact has been agreed, and the disagreement has quickly become public.

For Reform, the naval proposal offers a clear campaign message on an issue central to its appeal.

Whether it could become policy is a separate question, resting on French consent, maritime law and the ability to prevent dangerous crossings without creating a new crisis in the Channel.