With summer fast approaching, we are all starting to weigh up the risk of skin cancer against the tropical image of  reclining on a sun lounger by the pool.

However, more and more Britons have been found to have worryingly low levels of Vitamin D, ‘the sunshine vitamin’, in their systems. Increasingly indoor lifestyles are reducing our sun exposure to the point where supplements are required by many.

This deficiency has been linked to an increased risk of breast and bowel cancer – it is clear that sunshine is crucial for your health, but when do the rays become damaging?