France's lifeboat service refused to rescue 120 migrants on a mega-dinghy bound for Portsmouth because they said it would have put the asylum seekers' lives in danger. 

The Prefecture of Manche spent £90,000 on deploying five boats and two helicopters to shadow the rickety vessel from Utah beach in Normandy towards England's South Coast.  

Once the dinghy entered British waters, the migrants on board were picked up by two RNLI lifeboats which took them to Eastney ferry port, where they landed on Sunday to be met by hundreds of anti-migrant protesters. 

Four of the five boats shadowing the mega-dinghy belonged to the SNSM, France's equivalent of the RNLI. 

However, the French voluntary organisation refused to let the migrants board their own lifeboats after deeming it to be too risky - leaving the RNLI to do so instead. 

A spokesman for the prefecture said: 'Determined to reach the United Kingdom, migrants making the crossing in makeshift vessels refuse the assistance offered by French services and only accept it when faced with situations of extreme urgency.

'Given the structural fragility of the boats, which are consistently overloaded, the decision has been taken not to force migrants to board state-run rescue vessels, so as to avoid putting their lives at risk in the event of a shipwreck.'

Every ship and harbourmaster is bound by Article 98 of the United Nations convention on the law of the sea and the safety of life at sea convention to help anyone in distress in the water when their lives are at risk.

Distress is defined as 'a situation wherein there is reasonable certainty that a person, a vessel or other craft is threatened by grave and imminent danger and requires immediate assistance'.

Rescuers are meant to avoid attempting to board or redirect a boat if there is a danger it could capsize. 

But Shadow Home Secretary Chris Philp warned that France's failure to intervene in the early stages of migrant crossings was 'putting lives at risk'. 

'Around 100 people have died trying to cross the Channel already. The French could easily end this – they could stop the boats as they embark in knee-deep water, or stop them at sea near the French coast.

'The Belgians do this, and the Australians have done it in the past, with no loss of life at all. Allowing this to continue simply puts more lives at risk and allows the illegal crossings to continue. 

'Shabana Mahmood should not be paying £660m of our money while the French refuse to do what other countries will do.'

The two RNLI lifeboats were denied entry to two larger ports before docking near Portsmouth, it emerged yesterday. 

A broadcast on an open marine VHF radio revealed that Southampton Vessel Traffic Service and King's Harbour Master Portsmouth denied the RNLI permission to enter either port or their approaches and failure to comply could result in criminal prosecution.

The crews of the Bembridge and Yarmouth lifeboats therefore decided to sail several miles further along the coast and dock instead at Eastney, where the confrontation later unfolded.

Large crowds blocked traffic along the road leading away from the port in an attempt to stop the migrants reaching a processing centre in Kent. Police were seen carrying riot shields as they confronted the black-clad mob.

Hampshire Police Federation claimed two officers were pushed off motorbikes, while others had bricks thrown at them. 

The chaos came a day after masked anti-migrant protesters blocked traffic at the Port of Dover.

Hard-Right organisation Patriot Platform – run by convicted attempted kidnapper Daniel Thomas – claimed responsibility for the demonstrations in Portsmouth and Dover. 

The migrant 'mega-dinghy' had travelled about 70 miles from the Normandy coast, becoming the first migrant boat known to have completed such a lengthy crossing. Its route was far removed from the usual transit point between Calais and Dover.

The decision to land the migrants in Portsmouth has sparked a major row, with Portsmouth City Council leader Steve Pitt accusing the Home Office of 'poor judgment'.

He said: 'The Government needs to take more action to prevent small boat crossings. Clearly people are not happy with the situation and we respect everyone's right to protest, but it should be done peacefully and within the law.

'We are pleased the coaches were eventually able to leave Portsmouth early this morning to take people outside Hampshire for processing in the normal way.

'The council wasn't asked about the decision to land the lifeboats in Portsmouth. This was entirely a decision taken by UK Border Force, the Maritime and Coastguard Agency and the Home Office.

'It was a completely unsuitable location to bring the boats ashore. This entire situation was avoidable and has brought needless disruption to our city. I would like to thank the emergency services for their professionalism under very challenging circumstances.

'However, the Home Office has some serious questions to answer about its lack of planning, inconsistent decision-making and, ultimately, poor judgment. It put people at risk. This cannot happen again.'

There are now fears more dinghies will make the long-distance sea voyage from Normandy as smugglers evolve their tactics.

A senior French interior ministry source told the Daily Mail: 'The geographical focus of the people smugglers is definitely changing.

'They are finding it much harder to get boats launched in the Pas-de-Calais and so are moving west to Normandy.

'We expect far more of the mega-dinghies to appear here in the coming weeks and months. The success on Sunday proved the voyage can be done.'

Occupants of the Portsmouth dinghy, including 20 women and eight 'very young children', refused rescue after their outboard motor broke down, according to French officials.

A Home Office spokesman said: 'We condemn the intimidating and thuggish behaviour we saw in Portsmouth last night.

'The right to peaceful protest is fundamental to our democracy, but it must never cross the line into disorder. We thank the emergency services who safely managed this situation.

'This Government is doing the hard and necessary work of bearing down on small boat crossings, with the lowest number of arrivals between June and August since 2020.'

The RNLI helped more than 36,000 people across its lifeboat and lifeguard services last year, with crews launching more than 9,000 times to assist those in distress at sea.

RNLI lifeboat crews insist they have a duty to rescue anyone at sea, regardless of who they are.