“It’s all about saving money now, not just sustainability.”

Those are the words of the founder of a solar power firm who sums up the shift in the industry neatly. Ben Harrison’s Gloucestershire company has installed 65% more solar panels for businesses since the Iran war started, and energy bills soared.

Across the UK, the total amount of solar power installed has risen 11% compared to last year, according to government figures. For companies, the maths is simple.

In Somerset, the makers of the Henry vacuum cleaner have just spent £1.5m on new solar panels at their Chard factory. The financial director said he will get his money back “in less than four years”.

Fly low over a typical industrial estate and you’ll see plenty of solar panels on factory rooftops. But at the huge Numatic plant in Chard, they have gone to a new level.

They have just filled a whole field behind the factory.

There are 1,200 people working here, making Henry, the famous little red vacuum cleaner, and his pink friend Henrietta.

They make everything except the motors on site, from scratch. Moulding their own plastic and automated robotic production sucks power like, well a vacuum cleaner.

“Electricity is hugely expensive,” says Steve Whitlock, the firm’s financial director.

He is proudly showing me the brand new field of solar panels, 2,672 in all.

Until recently, it would be sustainability managers promoting this kind of work. But today, a solar installation costing £1.5m is “a major investment, like any other”, according to Whitlock.

Read more: BBC