An earlier points failure caused severe lunchtime rail disruption between London King's Cross and Stevenage.

Thameslink, Great Northern, LNER and Lumo passengers on trains travelling through the Stevenage area faced delays or cancellations this afternoon (July 12).

Disruption began at around 1pm with some trains delayed by around 45 minutes or more.

An earlier National Rail statement reads: "A points failure at Stevenage is causing disruption to journeys through the station.

"Services may be cancelled, delayed by up to 30 minutes or revised.

"Please allow extra time to complete your journey today."

The problem meant some trains were unable to call at Knebworth, according to Thameslink and Great Northern.

Departure boards show the points failure in Hertfordshire is impacted services to destinations across the UK, including Cambridge, Horsham, Brighton and York.

A National Rail update at 1.50pm read: "The points failure at Stevenage has now been rectified allowing services through this station to resume.

"Services may still be cancelled, delayed by up to 60 minutes or revised."

As well as localised disruption, Network Rail has warned that hot weather could impact trains nationwide when temperatures are set to reach highs of 30C or more this weekend.

A Network Rail spokesperson said: "On the railway, hot summers can be as challenging as freezing winters.

"Hot weather can affect the rails, overhead power lines and the ground which the track sits on.

"We work hard to get you to where you need to go, safely and on time by minimising the impact of hot weather on the railway."

They added that rails can expand, and to reduce the risk of causing damage, trains are sometimes asked to move slowly through hot areas.