Jeremy Corbyn insisted there was 'nothing half-hearted' about Labour's pro-EU campaign as he made his first major speech of the referendum battle.

Eastern Daily Press: Jeremy Corbyn MP visiting NTS (Norfolk Training Services).Picture: ANTONY KELLYJeremy Corbyn MP visiting NTS (Norfolk Training Services).Picture: ANTONY KELLY (Image: Archant Norfolk 2016)

The left-winger - who voted Out in the 1975 referendum and has expressed Eurosceptic views over subsequent decades - has been accused of making only a lukewarm contribution to the Remain argument so far.

But he said it was clear that the party was 'overwhelmingly convinced' that being part of the bloc was in the best interests of the country on issues such as workers' rights and the environment.

There remained serious 'shortcomings' that needed to be addressed by Brussels, such as the proposed trade deal with the US which gave 'huge cause for concern' about the potential for privatisation of public services, he warned.

All of those could be better dealt with, however, by remaining in the EU 'warts and all' rather than by pulling out and leaving the country at the mercy of the Conservatives, he argued.

'We have had a very big debate within the party and within the trade unions. Overwhelmingly, the Labour Party and the trade unions have come to the view that they want to campaign for a social, just Europe to protect the workers' rights that we've got, to extend them and extend that degree of justice.

'That is the position we have reached. That is the position that has been adopted by the party. That is the party that I lead and that is the position I am putting forward.'

He went on: 'There is nothing half-hearted about what we are doing, there is nothing half- hearted about our campaign, there is nothing half-hearted about our alliances.

'I have attended a number of meetings of the Party of European Socialists, I have had lengthy conversations with prime ministers and party leaders all across Europe on the social justice case, the environmental case, the issues of climate change, trade and steel and all those issues.

'I have made numerous speeches on all these subjects. There is nothing half-hearted about what we are doing.'

•Get more EU stories and vote in our In or Out EU poll here

Mr Corbyn said: 'Over the years I and many others have been critical of many decisions taken by the EU.

'And I remain very critical of its shortcomings, from its lack of democratic accountability to the institutional pressure to deregulate or privatise public services.

'So Europe needs to change. But that change can only come from working with our allies in the European Union.

'It's perfectly possible to be critical and still be convinced we need to remain a member,' he said, suggesting his own election as Labour leader - after years at loggerheads with the direction of the party - showed what could be achieved.

'I've had a few differences with the direction the Labour Party's taken over the past few years as some people may have noticed,' he joked.

'But I have been sure that it was right to stay as a member of the party. I joined the Labour Party when I was 16 and I am very proud of that.

'Some might say I've even managed to do something more recently about changing the direction of the Labour Party and I'm enjoying that as well.

'In contrast to four decades ago, the EU of today brings together most of the countries of Europe and has developed important employment, environmental and consumer protections.

'I have listened very closely to the views of trade unions, environmental groups, human rights organisations and of course to Labour Party members and supporters and fellow MPs.

'They are overwhelmingly convinced that we can best make a positive difference by remaining in Europe.

'Britain needs to stay in the EU as the best framework for trade, manufacturing and co-operation in 21st century Europe.

'But we also need to make the case for reform in Europe - the reform David Cameron's Government has no interest in, but plenty of others across Europe do.'