Media playback is unsupported on your device Media caption Trevor Bunney, RNLI: "One lady had the first signs of hypothermia."

Two British men have appeared in court charged with immigration offences after a boat carrying 20 people was rescued off the Kent coast on Sunday.

Robert Stilwell, 33, from Dartford, and Mark Stribling, 35, from Farningham, appeared at Medway Magistrates Court accused of people smuggling.

Those rescued included 18 Albanian migrants, two of them children.

An ex-chief immigration inspector said earlier people would die unless more were done to stop crossing attempts.

Mr Stilwell and Mr Stribling were charged with conspiring to facilitate the entry of non-EU nationals, and remanded in custody to appear before Maidstone Crown Court on 27 June.

The UK coastguard said it was called just before midnight on Saturday to an incident off the coastal village of Dymchurch.

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Those on board the boat reportedly alerted their families in Calais after their inflatable boat started taking in water.

Rescuers said a helicopter from nearby Lydd and two lifeboats from Dungeness and Littlestone were sent to the incident off Dymchurch.

Media playback is unsupported on your device Media caption The BBC understands this is the boat the 20 migrants were travelling on, as Catriona Renton reports

At about 02:00 BST on Sunday, a rigid-hulled inflatable boat or RIB with 20 people on board was found.

Trevor Bunney, who was part of the RNLI lifeboat rescue team, said the people they rescued were "a bit dishevelled, [had] obviously been at sea a long time and not in the best of conditions".

"One lady had the first signs of hypothermia," he said.

After being rescued, the group were handed over to the UK Border Force and taken to Dover.

A second vessel - which officials say could be linked to the incident - was discovered on the beach at Dymchurch.

'Not doing enough'

Since the rescue on Sunday, concerns have been raised that sea tragedies, similar to those seen on the voyage to Turkey, Greece or Italy, could occur in the English Channel.

There is an "equal chance" of migrants drowning in the Channel as in the Mediterranean, former chief inspector of borders and immigration John Vine said.

Mr Vine, who was chief inspector until 2014, said: "We have seen the tragedies that have occurred in the Mediterranean.

He added that the hazards of Channel sea traffic, weather and sea conditions "are going to mean there is an equal chance of people losing their lives unless this is stopped."

"Clearly if this is now the start of something new, then really that needs to be reassessed and resources need to be put in," he added.

Analysis

Image copyright Jon Wickington Image caption A second boat believed to be linked to the investigation was driven away from Dymchurch beach

By Simon Jones, BBC correspondent

Many people living along the Kent coast are shocked, but not surprised at what's happened.

The Channel is a huge stretch of water to patrol - and the authorities are often relying on tip-offs to try to catch those responsible.

Some residents are asking how many migrants are managing to get through without being detected.

The fear is that with the recent security clampdown at the Port of Calais and Eurotunnel, more and more migrants will attempt to cross the Channel on small boats, putting their lives at risk.

At the Port of Dover, the boat from which the migrants were rescued has been painstakingly examined.

It would have been a tight fit to get 20 people on board, crammed into the small craft in the busiest shipping lane in the world.

Damian Collins, MP for Folkestone and Hythe, however, said it was "too early to say whether this is a new trend".

He told BBC Radio 5 live it was wrong to say the UK's coastline was "undefended", saying the Channel was "probably the most monitored stretch of water in the world".

'Biggest onslaught'

UKIP Leader Nigel Farage said it was "essential that a clear message is sent that no migrant arriving on our shores by boat is allowed leave to remain".

"We have all seen the horrors of the Mediterranean, with thousands crossing and hundreds dying, we cannot allow that to happen off the shores of Kent and Sussex."

Lucy Moreton, general secretary of the Immigration Services Union, which represents border agency and immigration staff, said large stretches of Britain's coastline were being left unpoliced, and officials simply did not know how many migrants have entered the country undetected.

Her "gut feeling" and anecdotal evidence suggested Britain's coasts are facing the biggest ever onslaught of people smugglers, she said.

Sunday's incident comes after 17 men, thought to be Albanian migrants, were detained when a catamaran arrived at Chichester Marina in West Sussex on Tuesday, along with a 55-year-old British man wanted on suspicion of murder in Spain.

The Briton, who was the subject of a European Arrest Warrant, was detained on suspicion of facilitating illegal immigration and the 17 men were held on suspicion of entering the UK illegally.

Also last month, two Iranian men were found floating in a dinghy in the Channel.

Meanwhile, Greek coastguards rescued 29 migrants adrift off the island of Lefkada, in the Ionian Sea, as they attempted to reach Italy 150 miles (241km) away.

They are the first migrants known to have attempted the sea crossing from Greece to Italy since the northern land route via Macedonia was closed in March.