Britain's latest summer has been the coolest for 20 years – and to top it off there are warnings of more unsettled weather to come.

June temperatures averaged 13.8c, the Met Office said yesterday, with July averaging 15.8C so far.

If the rest of the month and August do not improve, the average for the entire summer from June to August will be just 15.1°C. That would make it the coldest summer overall since 1993, which averaged 14.9°C.

This has also been the wettest since 2007 and the dullest since 2008 based on the number of sunshine hours.

There has been 83.1mm on average across the UK – up around 15 per cent on usual with more following this month.

The Met Office said temperatures will begin dropping tomorrow a with thunderstorms and prolonged rain Friday and at the weekend.

Forecaster Brian Gaze of The Weather Outlook told The Sun: "I expect the mixed summer to continue with a real mixed bag of washout days with torrential rain and dry days with pleasantly-warm sunshine."