Organisers have called off races and modified athletics competitions as the UK's latest heatwave brings temperatures above 30C and prompts a rare red warning for extreme heat.

A number of road and trail races, athletics meetings and school sports days have been called off this week as the UK heatwave continues.

With a rare red warning for extreme heat coming into force in parts of England and Wales on Wednesday (June 24), some mid-week events have cancelled or postponed their competitions.

On Tuesday some schools athletics events were called off or cut short as temperatures hit 34C. One event in Gateshead saw teenagers running 500m instead of 800m, with the same meeting finishing earlier than planned, as teachers sought to protect students from the conditions.

It is no surprise given that more than 300 schools across England and Wales are closing fully or partially this week, whereas rail passengers are being asked not to travel unless absolutely necessary on Wednesday and Thursday.

Runners were notified of various cancellations, including the Corby 5 in Northamptonshire, Thruxton 10km in Hampshire and Lyme Midsummer Trail 10km in Cheshire – all due to take place on June 24.

Corby 5 organisers say they are looking into refunds and possible rescheduling the event, adding: "The safety and wellbeing of our runners, marshals, volunteers and officials must always come first. With the current forecasted conditions we do not feel it is right or safe to proceed."

Yeovil Olympiads has postponed their evening open meeting on June 25 and rescheduled it to July 2.

The Devon 10,000m and West Country Mile track meet on June 24 was also called off with organisers, City Runs, saying: "The welfare of athletes, officials and volunteers must come first."

The red warning area includes London, the south-west and south-east of England, the Midlands, Cardiff and the east of England with temperatures predicted to reach 38-39C.

The North West, North East and Yorkshire are subject to an amber warning.

Update on June 26: further British events cancelled or postponed this week include the Bedfordshire 10km, Epsom Oddballs 2000 Perch (multi-terrain 10km), Colworth 5, Run Media City 5km/10km in Salford, Bexhill 5km in East Sussex, Great Chalfield 10km in Wiltshire, Maldon 5km in Essex and South London Harriers Cross Country on Farthing Downs in Coulsdon.

The Paris Diamond League on June 28 will also have a modified programme due to the heat raging across France. More here.