Labour leader Jeremy Corbyn visited a camp in northern France to see first-hand the squalid conditions refugees and migrants are living in after fleeing war, poverty and persecution.
Mr Corbyn crossed the English Channel to head to the Grande-Synthe Camp, near Dunkirk, where more than 2,500 people are sleeping rough in the mud, wet and cold.
His 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".
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 in the swamp-like conditions.
He said: "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.
"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."
Mr Corbyn said Britain should be part of a pan-European effort to help the people affected by the crisis.
And he went on: "Germany has done an enormous amount, other countries have done varying amounts and I think we should be part of bringing European support to people."
The numbers of migrants and refugees at Grande-Synthe have steadily risen since last October, from around 800 people sleeping rough there to around 2,500 in recent weeks.
Most are Kurds from Iran, Syria and Iraq looking to cross to the UK, including some 250 children, according to Medecins Sans Frontieres.
The organisation took action in the face of what it called a failure by the authorities to offer decent living conditions to the masses camped there in ankle-deep mud.
Aid workers said people have been living in ultra-thin tents surrounded by puddles of water and food, which has attracted rats, prompting regular extermination operations.
Help and donations, including food, clothing and tents, have come from volunteers who often arrive at weekends from the UK, Belgium, Germany and the Netherlands.