The target itself is already bringing dividends. Firms like Mitsubishi and Clipper Wind are committing major new investments to build wind turbine factories in the UK. This means thousands of new jobs, both directly and in their suppliers. They see that the Government is serious and has a clear vision, and this creates the necessary confidence to invest in Britain for the very long term.

We also believe that having a clear target for renewable energy will help us to make faster progress because everyone – investors, Government, the regional development and skills agencies, and trade unions, know exactly what is expected of them. True, the target shows this will require a huge collective effort, but it will bring us enormous potential benefits as we shift to a low carbon future.

Here, I would like to thank the TUC and the trade unions for their strong support for a new, active industrial strategy that will bring real jobs back to our economy. Unions were among the first to see the huge employment opportunities from our new energy system.

However, renewable energy projects have high upfront costs. Investors are not going to take the risk if they don’t think Governments are serious.

This is why I am seeking cross-party support for the 15% renewables target – it’s too important to lose to uncertainty. Please help me if you can to call on the leader of the Opposition, David Cameron, to join me in making this firm pledge for the future, by cosigning my open letter to him – you can find more about this, and sign online on my Ed’s Pledge site.

We have a shared responsibility to tackle climate change. But the result will see the UK well placed to lead the world in major new green technologies.