The BMA has been campaigning against sunbed use since 2003, arguing that just one session a month doubled the average individual's annual dose of UV radiation.

BBC: Doctors criticise council sunbeds

Clearly, 20mSv is an unusual dose and not to be recommended, but it's not a significant dose for an individual or in public health terms.

BBC: UK 'can cope with solar superstorm'

The radiation dose from an individual dental X-ray, Dr Claus points out, has gone down by about half over the past 30 years or so.

ECONOMIST: Confirmation that dental X-rays can be bad for you