Onshore wind and solar power farms in the Forest of Dean could fuel almost 200,000 homes, according to new research.

Estimates from the National Grid suggest the UK must double the amount of renewable electricity it produces over the next six years to replace energy phased out from fossil fuels.

Climate and energy charity Friends of the Earth has called on all political parties to pledge to lift restrictions on onshore wind farms.

The campaign group said the Conservatives' track record on energy security is "woefully inadequate", and labelled Labour "increasingly shaky on climate" after it cut its £28 billion green investment pledge by half in February.

It has also urged local authorities to identify suitable renewable energy sites in local plans, and called for further investment in the electricity grid as a "top infrastructure priority".

Research conducted by Exeter University's Environmental Intelligence Centre and Friends of the Earth shows there is around 3.3 square kilometres of land in the Forest of Dean suitable for onshore wind farms.

There is also approximately 8.7 square kilometres capable of hosting solar power sites.

This would generate a total of 528 gigawatt-hours (GWh) of electricity, which would power around 195,700 homes based on average electricity consumption.

Across England, the research found 219,800 hectares of land considered most suitable for new onshore wind developments and 295,000 hectares with potential for new solar sites.

This could produce more than 12 times the current amount generated by solar and onshore wind power, fuelling 83.7 million homes.

Researchers excluded higher-grade agricultural land, which can be degraded by solar farms, and implemented a one-kilometre buffer around all grade one and two listed buildings, a two-kilometre distance from any registered park or garden, and a 500-metre ring around any scheduled monument.

The research also excluded all national parks and areas of outstanding natural beauty, and did not factor in solar panels on roofs.

Tony Bosworth, climate campaigner at Friends of the Earth, said: "Unleashing the UK’s immense potential to generate cheap, clean homegrown renewables is essential to bring down our energy bills for good and meet the UK’s vital international target to reduce carbon emissions by two thirds by 2030."He added: "We urgently need our political leaders to pull their heads out of the sand and produce a strong, ambitious and fair new climate plan that lifts the barriers to onshore wind and solar power and secures investment in the infrastructure needed to support the switch to renewables.

"These are win-win policies for creating long-term jobs, boosting our ailing economy and protecting our planet for future generations."

A Department for Energy Security and Net Zero spokesperson said: "Onshore wind power capacity has almost quadrupled since 2010 and renewables account for nearly half of our electricity, up from just 7%.

"We’ve also streamlined planning rules in England to make it easier for councils to identify suitable land for onshore wind.

"Our latest renewables auction has its largest ever budget of £1 billion, including a record £800 million pot for offshore wind, to further strengthen our world-leading clean energy sector, supporting a range of renewables from onshore wind to solar."