01/07/2015 05:03 BST | Updated 01/07/2015 11:59 BST

Hottest Day Of The Year 2015 Just Became The Hottest July Day Ever Recorded In The UK

Hottest July day with 36.7C recorded at Heathrow

Hottest day in Britain since 2006

Urgent health warnings issued

Train cancellations and slow-downs

Wimbledon reduces capacity in roaring heat

UK hotter than Barcelona and Athens

Urgent health warnings have been issued and commuters warned to expect delays as Britain sweets through its hottest July day ever recorded.

The Met Office tweeted just before 3:30pm it had recorded 36.7C (98F) at Heathrow.

Young children, the elderly and those with serious illnesses are at particular risk amid fears the hot weather could lead to hospitalisations and even deaths.

On the transport network, speed restrictions have been imposed by Network Rail on some train lines amid fears the metal tracks could buckle under the searing heat.

Virgin has cancelled 20 trains because of the rocketing temperatures as commuters brace themselves for what is predicted to be a chaotic rush hour this evening.

Photo gallery London Heatwave See Gallery