Wiltshire is one of the counties with the fastest growing number of solar panel installations, according to a trade organisation. 

The number of solar panel installations across the UK has almost doubled in a year, says the Solar Trade Association.

There are now almost 650,000 installations ranging from large-scale solar farms in fields to schemes on homes, schools and police stations, with electricity-generating photovoltaic (PV) panels on one in every 50 households across Britain.

The number of subsidised solar farms and large-scale arrays in England has soared from three in 2012 to 246 in 2014.

Development of small-scale solar has not been consistent, with just 0.5% of households in densely-populated London having panels installed compared to 3.6% in the South West.

The South West also has 2,933 arrays on non-domestic buildings ranging from small businesses to swimming pools, compared to the capital's 827.

But while the technology consistently enjoys support from more than 80% of the public, the large scale solar farms which have become an increasingly common feature of the English countryside have sparked some controversy.

Wildlife experts have urged Communities Secretary Eric Pickles to call in an application to install a 100,000-panel solar farm on rare grassland at Rampisham Down in Dorset, and campaigners warn of the cumulative effect of lots of solar farms in one area.

Most of the development of solar farms in England has been in the South West, with figures from CPRE suggesting, by last May, there were 98 schemes installed or in planning in Cornwall, 83 in Devon, 61 in Somerset, 30 in Dorset and 42 in Wiltshire.

A fundraising campaign for £2.7m to build a solar farm in Purton exceeded its target, with £2.9m being raised to support the array project Wiltshire Wildlife Community Energy (WWCE).

The scheme already has planning permission and will see a 5MW solar array built at Braydon Manor Farm.

The group has already built a solar array at Chelworth, which has produced average returns of 7 per cent for investors, with similar returns forecast for the Braydon Manor Farm project. 

Residents from Balcombe in West Sussex, at the centre of protests over controversial fracking, have turned to solar - installing 69 panels on a cow-shed as part of long term plans to generate enough power to match the village's entire electricity use.

Solar Trade Association chief executive Paul Barwell puts the popularity of solar panels down to falling costs, easy-to-understand technology and financial benefits - with home owners receiving "feed-in tariff" payments for power generated.

"There's an ongoing concern about energy price rises, not withstanding the very recent reductions in price, and people like the idea of being able to generate energy and becoming 'pro-sumers'," he said.

Some might consider the UK's overcast skies as an unpromising place for a solar boom, but its backers say it produces local energy, cutting transmission costs and imports, and southern England's levels of solar "irradiance" are similar to much of Germany which has six times as much PV installed.

Nick Clack, senior energy campaigner for CPRE, said the charity wanted to see solar PV sited on buildings where possible, and use of new technology such as solar film and tiles which can be integrated into new buildings.

He said: "We certainly see a much bigger role for solar on large roof tops which is pretty minimal at the moment. The Government is making the right noises in that direction, but they and others need to do a lot more to reduce the barriers to making that happen."

Of solar farms, he said: "We're not against them in principle, we think they can play a part in meeting our sustainable energy needs but it has to be done in the right way."

Where solar farms are developed, they should meet criteria including not harming landscapes or protected areas, avoiding affecting views from publicly accessible land and not be overlooked by housing, not use the best agricultural land and focus on brownfield sites such as old airfields, CPRE said.

The Solar Trade Association has a list of commitments its members should adhere to on solar farms, including focusing on low quality or non-agricultural land, promoting wildlife or continued farming such as sheep grazing, community engagement and minimising the visual impact of the sites.

Comparing solar farms to other energy sources, Mr Barwell said: "You can't hear them, you can't see them, you can't smell them, they should have good hedging all around."

The developing industry has been affected by numerous policy changes, including steep cuts to feed-in tariffs for households and the closure of the existing subsidy regime for new solar farms.

But with stable government policy, the technology's backers say it could soon become subsidy-free, with solar farms cheaper than gas powered plants in a few years.

"The rich prize for any government getting into power, having five years in government, will be taking this technology to a zero-subsidy regime," Mr Barwell said.

"And once battery storage technology gets off the ground, it will secure solar's long term future."