Jamie Byng in Calais children protest

Canongate c.e.o. Jamie Byng and authors Jeanette Winterson, Ian McEwan, Philip Pullman, Nick Hornby, Michael Morpurgo and Yann Martel, as well as actors Jude Law, Benedict Cumberbatch and Idris Elba, are among the signatories to an open letter to David Cameron calling for “urgent action” to help children in the migrant camp at Calais.

The 145 signatories urge the Prime Minister to step in and allow unaccompanied children living in the so-called "Calais Jungle" to be reunited with their families in the UK.

The letter states: “This is a humanitarian crisis that needs to be acknowledged as such and it is imperative that we do everything we can to help these innocent and highly vulnerable refugees, especially the minors, as swiftly as is humanly possible.”

The signatories are seeking to draw attention to the 291 unaccompanied children in the camp who have a legal right to join family in the UK, and are stuck in “a dangerous bureaucratic limbo with the imminent demotion of the Jungle on the horizon.”

On Monday 22nd February, the French authorities are due to demolish the southern part of the Calais Jungle which would destroy the temporary homes of more than 3,000 people. This section of the camp is predominantly occupied by unaccompanied children and families. A census conducted on Monday (15th February) by Help Refugees found 440 children living in this section of the camp, 291 of which are unaccompanied.

Byng told The Bookseller: “Jude [Law] and I went to the camp last Friday, and it was just clear when we were out there the scale of the senseless and inhumane treatment of people. Especially the children - they were lonely and confused and stuck in a really desperate situation. The government’s timescale of nine months [to sort out legal rights] seems entirely unacceptable. It’s only when you go out and see something with your own eyes that you realise something urgently needs to be done. You feel an obligation as fellow human beings to actually do something it.

"We felt that it was really important to do something proactively about it and draw as much support for it as possible. It’s amazing the letter has received so much support from so many high-profile people. It’s a very inspiring list."

Law said: “Last week I visited the camp and met some of these unaccompanied children who have no choice but to endure the horrific conditions of the Jungle. These are innocent, vulnerable children caught yo in red tape with the frightening prospect of the demolition of the Jungle hanging over them, David Cameron and the British Government must urgently work with the French authorities to allieviate this humanitarian crisis.”

Citizens UK has identified hundreds of unaccompanied minors in Calais who have valid legal claims to have their asylum applications processed in the UK

Simon Cuff at Citzens UK said the group is "hugely grateful" to the public figures who have "stood up and stepped out to help protect these refugee children."

He said: "There is no time to lose to reunite them with their loved ones before the demolitions begin in earnest. Help Refugees UK are doing an amazing humanitarian job on the ground, we’re working to help people access their legal rights - but this should not be falling to charitable organisations in the first place. Governments need to get in there, bring order to the chaos and create safe legal routes to protect people.”

"Those with rights to be with their families in Britain should be reunited with them, those without the right to the UK should receive specialist support and care from the French. Not chased off by police in riot gear.”

The letter is open for the public to sign at: www.refugees-welcome.org.uk/childrenofcalais/

The letter and full list of signatories can be seen here.