The union leaders asked the PM to "immediately condemn Turkey’s threats of invasion” and also help to “deploy an international force and enforce a No-Fly Zone”, the general secretaries declared.

The union leaders demanded "that the UK government take action to prevent an invasion of North and East Syria by Turkey and protect the very people who have protected us.”

Here is the full text of the letter from union general secretaries to the PM.

Dear Prime Minister,

We are writing in relation to last Sunday’s appalling announcement by President Trump that he intends to immediately withdraw US troops from Syria. This is a green-light to a Turkish military invasion of North and East Syria, which, as we have already seen in Afrin, will undoubtedly lead to ethnic cleansing and genocide of the Kurds as well as a resurgence of ISIS.

The international community owes the Syrian Democratic Forces a debt for their sacrifice in stopping and defeating ISIS and building peace and stability in the region, they are our friends and allies.

We therefore call on the UK government to immediately condemn Turkey’s threats of invasion and to work with the international community to deploy an international force and enforce a No-Fly Zone to prevent the imminent catastrophe and protect civilian lives.

If the Turkish invasion is not stopped, the SDF will be forced into a long and bitter war for survival against the second-largest NATO army. In the resulting chaos, tens of thousands of ISIS fighters will escape their current internment and resume their barbaric acts of terror across the globe.

We demand that the UK government take action to prevent an invasion of North and East Syria by Turkey and protect the very people who have protected us.

Given the gravity of the situation, we would appreciate an immediate response.

Yours sincerely,

Len McCluskey – General Secretary, Unite the Union
Tim Roache – General Secretary, GMB union
Dave Ward – General Secretary, Communications Workers Union
Mark Serwotka – General Secretary, Public and Commercial Services Union
Mick Whelan – General Secretary, Associated Society of Locomotive Engineers and Firemen
Manuel Cortes – General Secretary, Transport Salaried Staffs’ Association
Mary Bousted – Joint General Secretary, National Education Union
Kevin Courtney – Joint General Secretary, National Education Union
Paddy Lillis – General Sectary, Union of Shop, Distributive and Allied Workers
Mick Cash – General Secretary, National Union of Rail, Maritime and Transport Workers
Mike Clancy – General Secretary, Prospect
Ronnie Draper – General Secretary, Bakers Food and Allied Workers Union
Larry Flanagan – General Secretary, Educational Institute of Scotland
Doug Nicholls – General Secretary, General Federation of Trade Unions
Stephen Cavalier – Chief Executive, Thompsons Solicitors