Jude Law, Benedict Cumberbatch and a delegation of 40 faith leaders have urged the UK and French governments to act immediately to help unaccompanied children living in the refugee camp in Calais.

More than 600 children, 423 of whom are unaccompanied, are currently living in the 'Jungle', a sprawling makeshift camp inhabited by thousands of refugees and migrants hoping to make it across the Channel. According to Citizens UK, a network of faith groups, schools and colleges, at least 150 of these unaccompanied minors have family in the UK, and may therefore legally seek asylum in Britain. Just 70 of those cases are currently live.

A statement signed by Christian, Muslim and Jewish faith leaders, in addition to celebrities including actor Juliet Stevenson, children's author Michael Morpugo, Benedict Cumberbatch and Sophie Hunter and Jude Law, has called for an urgent response from officials on both sides of the Channel.

"We call on the British and French authorities to immediately make provisions for the safe passage of all the unaccompanied minors and refugee children identified by Citizens UK with verified family connections to Britain," the statement reads.

"These children have a full legal right to reunite with their loved ones. It is unacceptable that they are left in danger and distress for administrative convenience. The system established to reunite these families must either be set aside, or made to work as a matter of extreme urgency."

Every signatory of the statement has signed up to a 'buddy' system; promising to support one unaccompanied child currently in Calais and ensure they receive full humanitarian support. Under an initiative organised by a number of organisations including Citizens UK, Help Refugees and Good Chance Calais, they will write letters to both UK Prime Minister David Cameron and French President Francois Hollande on behalf of the child, visit them where possible and donate money to fund legal costs.

Salvation Army officer Nick Coke said of the pledge: "With evictions beginning in earnest and these minors' homes being demolished we must act urgently to ensure these children are not lost, scattered across Northern France and away from the humanitarian protection they need and the legal support they require to reunite with their loved ones."

Joe Murphy and Joe Robertson of Good Chance Calais, said: "Given the perilous position the camp sits in at this time, it is imperative that we work actively to use the legal routes to reunification as soon as possible."

The buddy scheme initiative follows a statement made by Hollande yesterday in which he said all children in Calais who had relatives in Britain "should go to the United Kingdom quickly and efficiently".

"We're glad that the President and Prime Minister have finally acknowledged the urgency of this problem," said George Gabriel, lead organiser at Citizens UK. "That these desperate children cannot be left in the chaos of Calais and should instead be reunited with their loved ones as a matter of the utmost urgency".

Campaigners have condemned the demolition of a large southern part of the Jungle over the past week. Violent clashes broke out in the camp as teams began dismantling shelters using crowbars and mallets and police fired teargas at people trying to stop the demolitions.