The Port of Calais has been temporarily closed after 100 migrants stormed on to a P & O ferry in a desperate bid to reach the UK. As the migrants attempted to board the vessel called Spirit of Britain, the shipping company reported a "security incident" as a result of a "migrant invasion."

In a video filmed by a bystander, crowds can be heard cheering as migrants try to force their way through the fence. Police reportedly used water canons on board the ship to try to force the migrants to leave. Witness Ben Ferguson said: 'Demonstrators broke police lines & headed to the port. In spite of clouds of teargas a group prised open fence b4 (sic) crowd followed.'

DFDS Seaways tweeted: "The Port of Calais has been temporarily closed due to a migrant invasion, as soon as they are cleared the Port will re-open. As a result our vessels are subject to delay of between 90 and 120 minutes."

The Port of Calais is resolving a security incident. As a result our vessels are subject to delay of between 90 and 120 minutes.

— P&O Ferries Updates (@POferriesupdate) January 23, 2016

A statement from the Port of Dover said the French port was experiencing "migrant activity" which had disrupted services. It read: "The Port of Calais is currently experiencing migrant activity which has caused disruption to ferry services. Therefore services to and from Calais via the Port of Dover are affected, but DFDS Seaways services are still running to Dunkirk as normal.

"The Port of Dover remains open for business, but the duration of this disruption to services remains unknown."

The Calais shut-down follows a protest march in support of the migrants living in squalid conditions in Calais. The protest, which was reportedly attended by 2,000 people, was in response to the increased police presence at the camps, which it is feared is a further threat to the refugees, after hundreds were forced out of their makeshift accomodations.

Migrant crisis
Migrants hold banners on January 23, 2016 in the French port city of Calais, northern France, during a demonstration to support the migrants and refugees who live in the \'jungle\', an encampment made up of migrants who are mainly trying to reach Britain AFP/Getty

The protest took place as British Labour leader Jeremy Corbyn visited the region, where 4,000 migrants are camped out in the hope of finding sanctuary across the channel in Britain. During his visit, Mr Corbyn was given a tour of the site meeting refugees and aid workers before speaking of the 'dreadful situation' faced by people camped living "in a sea of mud."

"What I'm trying to achieve here is to understand the nature of the refugee crisis that's facing the whole of Europe. Ultimately we deal with the situation by dealing with the problem at its source, which are the wars and conflicts," he said.

"Also, there are the human needs of people. We have got people here who have been here for months, if not longer than that, with no proper education, no access to doctors, no access to dentists, limited access to food - in very cold, very wet conditions. These conditions are a disgrace anywhere. We as human beings have to reach out to fellow human beings."

Plight of refugees in Calais & Dunkirk is an affront to our common humanity which demands action by both France & UK

— Jeremy Corbyn MP (@jeremycorbyn) January 23, 2016

Mr Corbyn's visit comes amid a growing urgency over the migrant crisis, with French prime minister Manuel Valls warning the huge influx is putting the European Union's future in 'grave danger'. He warned that the refugee crisis put the future of the European Union, whose key principle is the freedom of movement of people between countries, in "grave danger".

He told the BBC: "It's Europe that could die, not the Schengen area. If Europe can't protect its own borders, it's the very idea of Europe that could be thrown into doubt. It could disappear, of course - the European project, not Europe itself, not our values, but the concept we have of Europe, that the founding fathers had of Europe. Yes, that is in very grave danger. That's why you need border guards, border controls on the external borders of the European Union."

Migrant crisis
Corbn said the conditions at the camps \'are a disgrace anywhere\' AFP/Getty

Earlier, US President Barack Obama pledged his support to German Chancellor Angela Merkel's efforts to ease the refugee crisis in Europe. During a phone call with the German leader ahead of an upcoming donor conference, Obama said the US government would offer aid to ease the plight of migrants and refugees and "would contribute substantially."

The German chancellor will look to galvanise international support for refugees at a donors conference on Syria in London on 4 February, which she is co-chairing.

The British Government has helped fund French efforts at the camp, after a deal announced in August which also included measures to stop security breaches and ease the migrant crisis.

The number of migrants at the Dunkirk slum known as the jungle, has risen from 800 in October to 2,500 in recent weeks, most of whom are from Syria and Iraq.The UN says 13.5 million people in Syria are in need of urgent humanitarian assistance, while millions more have been forced to leave the country due to a bloody four-year civil war.