The European Union has driven renewable energy deployment and boosted the UK’s voice in the international climate debate Lord Mandelson has claimed as he made the case against Brexit yesterday.

Speaking at the launch of new analysis which suggested government policy was stopping the UK from realising the economic benefits of the global low carbon transition, the Labour Peer claimed the EU had already played a vital role in the adoption of renewable energy technologies.

“The European Union has been a tremendous global leader on green issues and has amplified the UK's voice and effectiveness in the international climate debate – a really important role,” he said.

“It's also driven the development of the low carbon economy through the EU wide renewables targets and continues to do so through the circular economy directive.”

Reminiscing on his four year tenure as european commissioner, Mandelson explained that the UK had helped bring climate issues to the attention of the Commission following an informal meeting in 2005, leading to the roll-out of green policy in the following years.

“I was a member of the Commission at the time and it put climate change, green issues and renewables [higher] in the priorities of the Commission as a direct result of that informal special council meeting at Hampton Court in the autumn of 2005,” he said.

“So those that portray the European Union as an un-listening, inflexible, unresponsive, politically tin-eared organisation should just bear in mind that the EU is not a federalist organisation but a highly political one.

“When the member states of the EU really want to use it in order to pursue serious policy goals, they have the ability to do so and the Commission becomes very responsive,” he added.

The former Cabinet minister went on to claim a vote to leave would damage the UK’s standing on the world stage.

“If we came out of the EU the rest of the world would think we'd taken leave of our senses, that we've completely lost the plot. The world operates now not in silos but across borders, it operates in teams not individuals,” he claimed.

“If we remove ourselves from our own locality and the teams and expertise that we have built up and all the different component parts people are going to look at us differently.”

While he was unable to make clear what this difference would have on the UK, he claimed it was a “vital necessity” that the UK remained in the EU and it’s single market in order to attract investment.

“Major international investors are quaking in their boots as we approach the vote on 23 June,” he added.

Energy policy has been largely absent from the referendum debate, with immigration and the wider economic argument holding sway over many voters. Speaking recently to the energy and climate change (ECC) select committee, Antony Froggatt, senior research fellow for energy, environment and resources at Chatham House, said: “You haven’t seen a high priority given to energy issues.”

As one of the leading government figures on the Brexit side, energy minister Andrea Leadsom has argued that leaving the EU would allow the UK more freedom over its energy policy.

In a speech delivered on 17 May, Leadsom said: “We are world leaders in the development of new, low carbon technologies. Not only that, but our emissions reduction ambitions, set out in our own UK Climate Change Act of 2008, are world leading.

“So let me be very clear.  Absolutely none of this is threatened by the UK voting to leave the EU on June 23rd.”

She went on to claim that leaving the EU would allow the UK to mee its climate change targets at a faster rate as it would be divested from the requirements of EU State Aid approval, which she said is required when the government wishes to make policy regarding the UK’s energy mix.

“The Capacity Market that ensures our electricity supply, the Contracts for Difference auctions that support new renewables, even our new nuclear ambitions, all have to be approved under EU State Aid, a process that can take months or even years leaving us unable to efficiently address issues of value for the bill payer,” she said.

“Leaving the EU will give us freedom to keep bills down, to meet our climate change targets in the cheapest way possible, and of course, keep the lights on.”

However, Michael Grubb, professor of international energy and climate change policy at University College London, told the ECC select committee that the minister’s claims that UK energy security was dependant on the EU were “frankly somewhat misguided or even disingenuous.”