The future of the Galloper wind farm was left in doubt last year when energy company SSE pulled out of the project, blaming the cost and the subsidy regime. The remaining partner, RWE Innogy, halted work.

But RWE Innogy announced on Friday that Siemens Financial Services and the investment and financial services group Macquarie Capital, along with the UK government’s Green Investment Bank, had become joint 25 per cent equity partners.

Offshore wind is one of the few parts of the UK renewable energy sector to have emerged unscathed after a round of cuts to onshore wind and solar power subsidies since the first majority Conservative government since 1992 took power in May.

Scheduled to become operational in March 2018, Galloper will become one of the larger offshore wind farms in British waters with a capacity of 336 megawatts, or enough to power 336,000 homes. The announcement follows Dong Energy’s confirmation on Wednesday that it was going ahead with an extension to a wind farm in the Irish sea that will make it the world’s biggest.

Together, the two projects mean that there is 10 gigawatts (GW) of offshore wind capacity built, under construction or with financing secured in Britain, double the current operational capacity of 5GW, said the trade body RenewableUK.

Hans Bünting, the ceo of RWE Innogy, said: “Today’s announcement is the culmination of many months of successful negotiations with our partners and investors and shows that the UK is still a strong market for offshore renewables.”

The company has previously warned that political uncertainty and changes to policy have put the technology at risk in the UK.

While the UK has the most installed offshore wind power in the world, other countries are catching up. In the first two quarters of 2015, Germany installed three times as much offshore wind capacity as the UK.

The energy minister Andrea Leadsom said of the Galloper deal: “This milestone shows how the UK’s offshore wind industry is going from strength to strength.”

RenewableUK welcomed the news but said it needed a clear plan from the government on how much offshore wind capacity it wanted into the 2020s. In September, the government turned down planning permission for a much larger (970 MW) wind farm off the coast of Dorset.

A consortium of 12 commercial banks and the European Investment Bank will provide Galloper’s £1.37 billion debt facilities. The EIB has provided £225 billion in backing.