Invading migrants who stormed the Channel Tunnel in a desperate bid to break into Britain by force managed to get ten miles before they were caught, it has emerged.

A group of around 110 migrants, thought to be from Sudan and Eritrea, broke down security fences, pelted police with stones then made a dash for the tunnel in the early hours of Saturday morning.

They were eventually stopped by French gendarmes, who were able to stop the group by force in a battle some 250ft below the sea.

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Round-up: Security agents are pictured bringing back migrants who tried to break into the Channel Tunnel as part of a huge invasion attempt early Saturday morning

Amassing: Large numbers of migrants are pictured above outside a ferry port, advancing on lorries which have been stopped before reaching the UK

Detectives suspect the desperate charge was masterminded by far-left activists who have embedded themselves in the migrant camps surrounding Calais, some of whom are though to be British.

A French government official told MailOnline that 113 migrants made it into the tunnel, with the most successful making it 10 miles in - just under a third of the total 31.4-mile length.

Fabienne Buccio, prefect for the Pas de Calais region, said they went a ‘distance of up to fifteen kilometers before being stopped by the gendarmes'.

'Clearly organised': A tunnel spokesman said the group appeared to know what they were doing. The attack, he said, was so large that it had no real chance of success, but could be designed to attract attention

Broken fences: Traces of the track invasion could be seen Saturday morning around the tunnel site

Officers are thought to have pursued the migrants through the crossing's service service tunnel, which is wide enough for them to drive cars through to overtake them.

Ms Buccio said there were 113 migrants involved, all originally from countries such as Eritrea and Sudan. Around 200 are thought to have attempted the original charge, with security forces managing to hold back 80 of them.

Some 23 were arrested, while seven were treated for injuries, along with two police officers and a security guard.

Later on Saturday, hundreds of migrants living in illegal camps around the port town could be seen throwing stones at lorries, and then trying to clamber aboard them when they stopped.

A Eurotunnel spokesman said that the 'large and co-ordinated' group stormed the tracks at Calais at around 12.30am local time, causing the service to be put on hold for almost eight hours.

Another try: A dozen migrants try to pile in the back of a lorry they have identified at the Calais ferry terminal

Over the top: Two migrants climbed on top of the cab of this lorry, which has stopped near the terminal

And according to French officials, political activists embedded among desperate migrants in Calais were instrumental in persuading them to adopt more extreme tactics to break in to Britain.

The disruption has caused massive delays to passengers stuck on the Eurotunnel, with some set to be stuck in carriages with no access to food or drink for as long as three hours.

Migrants are still through to be hiding inside the tunnel Saturday morning in a desperate attempt to reach the UK, causing further delays while they are flushed out.

A Eurotunnel spokesman described the onrush as 'a massive invasion and intrusion by a very large and co-ordinated group of migrants'.

A French emergency services spokesman on the ground in Calais said political activists were 'co-ordinating' the invasion.

He said: 'They were very clearly helping to break down fences and guiding the migrants in a coordinated attack. They got into the south tunnel, and the service tunnel.

‘Fighting broke out with security guards, and we had to treat around ten migrants. Five ambulances were at the scene.’

Asked about the presence of anarchists, a Eurotunnel spokesman said: ‘It’s very likely that this was an operation designed with the goal of attracting public interest.’

In August, police warned of British anarchists living in Calais who were ‘manipulating’ migrants into using more aggressive tactics.

The head of a major police union said he believed attempts to storm the Channel Tunnel were partly organised by British left-wingers.

Gilles Debove, from the union Unite SGP-Police FO, said: ‘This is being encouraged not by human traffickers, who wish to remain discreet, but by extreme left elements here to manipulate the migrants in the name of their ideal of imposing a country without borders or police. Among these activists are quite a few Britons.’

Eurotunnel bosses stopped all trains overnight. The first train left the UK around 8am, and service is gradually being restored, albeit slowly.

Back eventually: The attack shut down train services between the UK and France for around eight hours

Inspection: Police officers examine broken fencing where the migrants broke through

Travellers have been offered a full refund. They were initially told they could use their tickets on ferry services, but space soon ran out, leaving passengers stranded.

Describing the attack, a spokesman said: 'It's clearly an organised attack when it comes in such a large number, there are over 100 in this one group.

'They arrived together and in a well-organised manner broke through the fences and all clearly knew where they were going.'

Going nowhere: Sean Dunlea, a 19-year-old headed to Belgium for a motorbike race Saturday morning, was stuck on this frain in Folkestone, facing delays upwards of three hours

Stuck: A van driver rests his head on his hand as he settles in for the long wait

Eurotunnel has implemented extra security to try to prevent migrants getting onto the tracks.

'Quite probably because the security at the tunnel is strengthening every day, with the new fences being put up, new security installations and additional staff, it's becoming much harder for migrants to get through in small numbers,' the spokesman said.

'This looks like quite a carefully co-ordinated and organised attack, possibly to raise the profile of their situation or as a last-ditch attempt before the new fences are up.'

Frustrated Britons were left feeling the brunt of the invasion, and face significant delays to their plans.

Sean Dunlea, a 19-year-old on his way to compete in a motorcycle race in Belgium, spoke to MailOnline from inside a train held up in Folkestone.

Mr Dunlea set off from Chelmsford, Essex, at 5:30am, and hoped to reach France by 10:30am local time.

'Invasion': Eurotunnel said a large group of migrants stormed the Channel Tunnel, one entrance of which is pictured above in a file photograph

Delays: A queue of lorries could be seen this morning being held up outside Cala

He was due to get on the car shuttle train just before 8am, but was delayed an hour getting on.

Two hours later the train had still not left, with officials none the wiser as to when they could continue. The car shuttles are equipped with toilets but have no supplies of food or drink.

Mr Dunlea said: 'Nothing's happening. I don't think any of us have a clue what's going on.

'We were headed to Belgium, because I'm a bike racer. I was meant to be happening this weekend - not any more. We are literally just sitting here - our plans for today are wrecked.

'We can't really get off and walk - there's no provisions. There's toilets but not really enough'.

His train finally started moving at 11am - just over three hours after the scheduled departure.

Thirteen migrants have died trying to reach Britain since the start of the crisis in June.

An Eritrean man in his 20s, was killed on Wednesday and is believed to have been hit by a freight train near the tunnel entrance at around 1am.

Early on Tuesday morning a 20-year-old Iraqi man was crushed to death after apparently sneaking on board a lorry to reach the UK.

Migrant crisis: Pictured are tents shrouded by fog in the 'new jungle' of a huge migrant camp in Calais

The HGV driver discovered the body in the back of his vehicle near Calais port as he inspected his load after he was forced to brake suddenly.

An estimated 5,000 migrants displaced from countries including Syria, Libya and Eritrea are believed to be camped in and around Calais.

At its peak, the number of attempts to board lorries or trains was around 2,000 a night - but that has since fallen.