Delayed passengers at Birmingham New Street yesterday

There's more disruption forecast for long suffering commuters on the rail network this week. This time though it's not leaves on the line or the wrong type of snow that's to blame - but the extreme heat.

The soaring temperatures have led to some journeys being delayed or cancelled.

This morning : Breakfast's Jules Botfield was at Birmingham New Street station.

Jules explained just why the trains can't run on time in the heatwave.

Network Rail has imposed the 60mph speed limit on the train operating companies - whose rails are being baked in the current heatwave.

We operate within a range and the very high temperatures have gone outside that range Peter Henderson, Network Rail

Most of the trains affected will be those due to run in the afternoons and early evenings - as these are the ones that would have to run on the very hot rails.

The problem is that in the current weather, the rails are in danger of buckling - which could cause a train to derail.

The rails are able to cope with variations in temperature - but the very high temperatures of the heatwave could be too much for them.

Breakfast reporter Jules Botfield has the latest, live from Birmingham New Street

In Birmingham, Jules Botfield reported that the disruption, had not yet started this morning - but that so long as the sun shines today, then delays are to be expected.

Almost all lines across the country are expected to be affected today, though some will be worse hit than others.

Those which are expected to be worse affected are lines in Southern England, East Anglia and the West Coast mainline.