By Alistair Bunkall, Defence Correspondent

Sky News – 10 May 2016

Five former secretaries general of NATO have published a letter supporting Britain's continued membership of the EU. Lord Carrington, Javier Solana, Lord Robertson, Jaap De Hoop Scheffer and Anders Fogh Rasmussen have written to say:

"Given the scale and range of challenges to peace and stability we collectively face, the Euro-Atlantic community needs an active and engaged United Kingdom. At a time of such global instability, and when NATO is trying to reinforce its role in Eastern Europe, it would be very troubling if the UK ended its membership of the European Union.

"While the decision is one for the British people, Brexit would undoubtedly lead to a loss of British influence, undermine NATO and give succour to the West's enemies just when we need to stand shoulder to shoulder across the Euro-Atlantic community against common threats, including on our doorstep."

The letter, which was distributed by Downing Street, comes a day after David Cameron gave a speech defending Britain’s membership of the EU asking:

"Can we be so sure that peace and stability on our continent are assured beyond any shadow of doubt? Is that a risk worth taking? I would never be so rash as to make that assumption."

But senior Conservative Dr Julian Lewis, the Chairman of the Defence Select Committee, has accused the Prime Minister of entering

"some sort of Alice Through The Looking Glass world. The real deterrent to an outside aggressor is very clear: it is the United States belonging to NATO.

"What the European Union is trying to do by building a common foreign and defence policy is trying to duplicate NATO without the involvement of the United States and that is highly dangerous."

Last month, in an interview with Sky News, the current NATO Secretary General Jens Stoltenberg said:

"A strong UK at the heart of Europe is good for NATO."

The letter is the first time so many former secretaries general have written together. Between them they led the alliance during the Cold War and following the 9/11 attacks.