UK's biggest solar farm comes online – but will it be the last?

The forecast for Cornwall is patchy: clouds, showers, even rain.

But drizzly weather will not take the shine out of Britain's biggest solar farm, which is connecting to the grid near Truro today, just in time to qualify for the last of a generous subsidy scheme from the Government.

The 7.2-acre, 1.4-megawatt scheme is on the site of a disused tin mine and will power 430 local homes from its 5,680 photovoltaic panels. It is the largest solar installation in Britain and one of up to 10 large-scale schemes being rushed into service before subsidies for commercial solar energy projects are controversially cut off at the start of next month.

The Coalition says it is necessary to slash the "feed-in tariff" (FiT) by up to 70 per cent for solar installations of more than 50 kilowatts (kW) to avoid large-scale farms hogging the available subsidies. The solar industry has described the move as "a horrendous strategic mistake" which will destroy the business case for investors, strangling the industry at birth. And 81 per cent of respondents to the Government's formal consultation process disagreed with the new arrangements.

The Wheal Jane solar farm, which makes use of contaminated industrial land, is emblematic of the opportunity the Government is missing, according to Derry Newman, the chief executive of Solar Century, which designed and installed the panels.

"The knee-jerk reaction by government to eliminate this kind of renewable power demonstrates a dreadful lack of ambition for our clean energy future," Mr Newman said. "After this summer, nothing like this, or even mid-scale solar on roofs, will now be built in this country for a number of years."

Ccampaigners' attempts to combat the changes, both through Parliament and the courts, have come to nothing. The only chance left of a reprieve is through an early-day motion tabled in the House of Commons last week by Labour's energy spokesman, Huw Irranca-Davies, the MP for Ogmore

The Wheal Jane project was developed by Lightsource Renewable Energy as part of a wider scheme to turn the old mine site into a business park using energy from solar, wind, hydroelectric and geothermal sources. Funding for the £4.2m solar scheme was put together by Octopus Investments.