The government points out that its proposed reduction in feed-in tariffs for large solar arrays will not apply retrospectively. Only new entrants after August 1 this year will be affected by the plans.

But it can take 12–18 months to set up a big solar power scheme. In practice, plenty of companies are part of the way through the process of securing planning permission from local authorities and connection permits from network operators.

They will already have spent large sums of money – yet the proposed changes could rob their schemes of any commercial viability. Philip Wolfe is the founder and managing director of Ownergy, a company that helps customers install and maintain solar arrays.

Greg Barker, the UK energy minister, has completed his review of subsidies for solar power under the feed-in-tariff scheme, and, as expected, he has reduced the amount of money available for installations that provide over 50kW.

Ministers say the idea behind this review is to make sure that large-scale solar farms don’t hoover up money that was meant for households and small businesses to install a small amount of solar power (usually with solar panels on roofs).