BBC: The first weather health alert of the summer has been issued as temperatures soared in parts of the UK. Temperatures peaked at 31C (87.8F) in Gravesend, Kent, on Friday and similar temperatures are expected in south-east England on Saturday. The Met Office said the main health risk would be stifling temperatures at night of20C (68F) in some places. “It is the night-time values which are of real concern,” said head of health forecasting Wayne Elliott. “High …