A group of eight people have been detained by immigration authorities after crossing the Channel in an inflatable dinghy.

A coastguard search had been launched off the Kent coast on Monday when the empty vessel was found on the beach at Dungeness shortly after 8am, but was stood down after it became clear no one had been left stranded in the sea.

Hours later, police and Border Force personnel were seen three and a-half miles away in the town of Lydd with some of the men, who were offered foil blankets to keep warm.

The Home Office said a ninth man, who was also found in the area, was arrested on suspicion of facilitating illegal entry to the UK. It added that seven of the men were in Border Force care and the eighth had been taken to hospital.

The development comes after a focus has fallen on recent channel crossings using small boats. The home secretary, Sajid Javid, last month declared the rising number of people attempting to cross the Channel to be a major incident and announced plans to move two Border Force cutters to take part in search and patrol operations.

The navy vessel HMS Mersey, which was on patrol on Monday morning, is being used to guard the Channel until the cutters return.

The rigid-hulled dinghy in which the men had travelled was discovered on a remote beach at Dungeness on Romney Marsh, Kent, with life jackets and fuel inside.

While armed police and Border Force personnel were in attendance, The south-east coast ambulance service said it was called to Dungeness Road at 12:20 GMT after “reports a number of people needed medical assessment having come off a boat”.

A Home Office spokesman said: “Border Force was contacted by HM Coastguard this morning, Monday 7 January, at around 8.20am after they received reports of an unattended RHIB (rigid-hulled inflatable boat) at Dungeness, Kent.

“Border Force officers were deployed to secure the vessel. A search of the local area found eight people. Seven of those are now in Border Force care and the eighth has been transferred to hospital.

“A ninth man, who was also found in the area, has been arrested on suspicion of facilitating illegal entry to the UK. The incident is currently being investigated by officers from Immigration Enforcement’s criminal and financial investigation team.”

Of the 504 people who tried to cross the Channel in 2018, 276 managed to get to British waters and coasts, and 228 were intercepted by French authorities. Most were Iranian, according to the French interior ministry.