With temperatures expected reach the high 30s this week, National Rail has said that train journeys are likely to be impacted.

A message posted on its website read: "When rail track temperatures exceed a certain temperature, speed restrictions must be put in place to prevent the track from buckling.

"This may cause delays and cancellations to journeys across the whole network until the end of the week."

So how is this expected to impact Southern and Thameslink commuters?

Well National Rail said that speed restrictions put in place would largely affect trains on the mainline route between London Victoria / London Blackfriars, East Croydon, Gatwick Airport and Brighton.

"The restrictions will vary in impact," the message read.

"Some of them will reduce train speeds considerably (for example, 20mph restrictions), but others are not so noticeable.

"However, it's expected a number of trains will lose time between London and the south coast.

Passengers have also been advised to carry a bottle of water with them while travelling.