The amber warning is in place for England and parts of Wales, with record temperatures predicted in the coming days.
The chief executive of the College of Paramedics has warned that the "ferocious heat" the UK is predicted to experience over the next few days could result in people dying. A total of 21 operators - ranging from Transport for Wales and Gatwick Express to the Transpennine Express and Southern - said they will be running a slower service on Monday and Tuesday after National Rail implemented speed restrictions across its network.Those who have to travel are being encouraged to check their journeys on the National Rail website before setting off and taking water with them to stay hydrated.
Train companies need to make their tiny minds up.