Dr Weller is supported by Martin Feelisch, the professor of experimental medicine at Southampton University who has also been studying sunshine’s role in keeping us healthy — in particular the effect of sunlight-stimulated nitric oxide to protect our cardiovascular systems by lowering blood pressure.Professor Feelisch warns that avoiding sunlight or using sunblock constantly could be a new risk factor for heart disease — and more people die from heart disease than skin cancer.

‘We believe current public health advice, which is dominated by concerns of skin cancer, needs to be carefully reassessed,’ he argues.

‘It’s time to look at the balance of risk for skin cancer and cardiovascular disease.’We should also be more sparing in our use of sunscreen as it may block the benefits of sunshine, Dr Lindqvist says.

We all tend to feel happier when the sun is out, and this is not simply a matter of morale.

Research shows that the main wavelength of light in sunlight stimulates sensors in our retina which regulate our body clock.

Such inflammation results from our immune systems fighting infectious invaders.

But this comes at a cost — as the tissue damage caused by long-term inflammation can itself cause disease.

The Cambridge research indicates that sunlight may prompt our bodies to switch down the inflammatory response.

Scientists are discovering sunlight may even help us keep slim and healthy, according to studies by the Universities of Southampton and Edinburgh that kept mice on high-fat diets while they were exposed to the spectrum of ultraviolet light found in sunshine.

But new research indicates that solar rays benefit our bodies in multiple other ways.

Scientists now believe, for example, that exposure to sun prompts our bodies to produce nitric oxide, a chemical that helps protect our cardiovascular system — and the feelgood brain-chemical serotonin.

Last year, Cambridge University scientists showed that the expression of 28 per cent of our entire genetic make-up varies from season to season.’The Cambridge investigators reported in the journal Nature Communications that in winter we increase the activity of inflammatory immune-system genes — to combat infectious bugs — and in summer we increase the activity of anti-inflammatory genes.