Lord Neil Kinnock, former Labour leader
Lord Kinnock has joined Margaret Beckett, David Blunkett, Jack Straw and Hilary Benn in penning the open letterGetty

Five senior Labour figures have backed David Cameron's EU deal to keep Great Britain in the Eurozone. In an open letter published in the Sunday Mirror former Labour leader Neil Kinnock, Margaret Beckett, David Blunkett, Jack Straw and shadow foreign secretary Hilary Benn have all thrown their weight behind keeping the UK in the EU.

All five of the Labour grandees campaigned for the UK to leave Europe during the last EU referendum over 40 years ago in 1975. The cross-party group Britain Stronger In Europe has affirmed that the Labour Party are now "united on the issue of Europe under Jeremy Corbyn's leadership".

The support of the five is a major endorsement for Cameron's EU deal, which has been criticised from some quarters as not being tough enough on benefits for new migrants and not fully addressing UK sovereignty in law-making and implementation. Even Cameron's own MP's have expressed concern about the deal with outspoken eurosceptic backbencher Jacob Rees-Mogg, describing the new terms as "thin gruel has been further watered down".

Hilary Benn
The backing of shadow foreign secretary Hilary Benn will be seen as a major endorsement for Cameron's EU deal Getty

The five said: "It's clear Britain is stronger, safer and better off than we would or could be if pulled out of the EU. The conclusion of the current renegotiation will hopefully strengthen this relationship as we make the progressive case for Britain in Europe."

The letter has been published as a new ComRes poll for The Independent On Sunday and the Sunday Mirror suggested that six out of 10 people do not think Cameron will get a good deal from renegotiations set to take place in Brussels.

Lord Kinnock lost Labour to general elections against Tory PM's Margaret Thatcher and Sir John Major, whilst the other four heavyweights all held Cabinet posts in the last Labour government. shadow foreign secretary Hilary Benn is set to formulate Labour's EU campaign strategy.

Neil Kinnock, Margaret Beckett, David Blunkett, Jack Straw and Hilary Benn's open letter

In the 1975 referendum we all campaigned against remaining in what is now the European Union.

Now, and for a long time past, it has been clear Britain is stronger, safer and better off than we would or could be if we pulled out.

Our concern then was that membership would mean a one-way loss of sovereignty and investment. This has proved unfounded.

We are part of an economic partnership with 27 other democracies, exercising full rights to determine agreed rules in the world's largest single market.

That has brought three million jobs, it attracts large investment, promotes growth and provides for employment rights that protect British workers.

We also have control of our currency, borders, security, defence, foreign affairs and justice.

Britain's voice on global matters, whether debt relief, peace-keeping or climate change, is amplified by being part of Europe. Intelligence sharing helps us fight terrorism and other crime.

The conclusion of the renegotiation will hopefully strengthen this relationship as we make the progressive case for Britain in Europe.

Leaving would be a huge risk to prosperity, security and the opportunities of future generations.

The EU is not perfect and improvement is always worth making, but the benefits far outweigh the costs.

– Neil Kinnock, Margaret Beckett, David Blunkett, Jack Straw and Hilary Benn