Trespassers gained access to the railway at High Wycombe this morning, Wednesday, May 27, at about 6.30am, forcing the train operator to halt all services on the lines towards London and the West Midlands.

All trains travelling between Oxford and London Marylebone, which call at High Wycombe, have been delayed this morning.

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Chiltern Railways said all lines reopened at about 7.50am but disruption is expected to continue until 9am.

The 6.38am train from Oxford to London Marylebone is delayed and due to depart at 8.03am, along with the same service at 10.19am, due to leave at 11.43am.

Services from Birmingham Moor Street to London Marylebone and vice versa are delayed by around two hours.

Chiltern Railways tickets are being accepted at no extra cross on Arriva Cross Country services between Birmingham new Street, Leamington Spa, Banbury, Oxford and Reading stations.

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A statement from Chiltern Railways said: “We’re sorry for the delay to your journey.

“If you have been delayed by 15 minutes or more, then you are likely to be entitled to compensation. Claims can be made online at delay repay.”

Customers are advised to check their journey before they travel on the Chiltern Railways JourneyCheck website.

Chiltern Railways cancelled its 4.37pm service to the West Midlands from Marylebone in Banbury at 5.38pm on bank holiday Monday.

Passengers reported the air conditioning had broken, with the sweltering conditions becoming unbearable inside the carriage.

A Chiltern Railways spokesperson said: “We are sorry that due to a fault with the air conditioning on a train, the 4.37pm service from London Marylebone to Stourbridge Junction on Monday, May 25 was cancelled at Banbury.

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“Customers were able to use their ticket to board the next service to the West Midlands which departed Banbury 50 minutes later.

“We encourage customers who were delayed as a result of the disruption to claim compensation via the Delay Repay scheme.”

The next service to the West Midlands departed Banbury at 6.27pm.

Staff handed out bottles of water to dehydrated passengers on Banbury’s platform.

The Daily Mail reported temperatures got up to 45C on the train.

Oxfordshire was one of nine counties where temperatures rose above 32C on Monday amid an historic bank holiday heatwave.

Records for May temperatures were broken at RAF Benson and RAF Brize Norton, where temperatures reached 33.6C and 32.9C respectively.

Until Monday, the highest May temperature had been 32.8C which was last reached in 1922 and 1944, the Met Office said.