Blistering temperatures expected in Britain during the next few days could buckle train tracks.

Network Rail is introducing speed restrictions on some railway lines from 11am this morning until Saturday because of the hot weather as engineers fear the steel tracks could expand and warp.

Slower trains could delay commuters.

One of the most sensitive sections for heat damage in Kent is the line to Sheerness where it crosses the Kingsferry lift bridge on the Isle of Sheppey.

When temperatures have become too hot in the past, the bridge has expanded and has been unable to slot back into the road, causing delays on the A249.

Engineers have been forced to cool the tracks by pumping gallons of water over them from The Swale.

Andy Thomas, managing director of England and Wales at Network Rail said: “On very sunny days, rails in direct sunshine can be as much as 20 degrees centigrade above air temperature causing the steel to expand markedly and could, if not carefully monitored and action taken, buckle causing travel disruption.

“Our engineers and specialist extreme weather teams are monitoring track-side temperatures and vulnerable locations and will, if necessary, introduce temporary speed restrictions during the hottest part of the day to keep trains running, albeit more slowly than normal.”

Temperatures could reach a sweltering 33C this week, making Britain hotter than Benidorm as high pressure sweeps into the UK, according to the Met Office.

Thermometers are predicted to peak today and tomorrow.

Health experts have warned sun-seekers to slap on the sun-screen to protect themselves from burning.

Those with hay fever can also expect to suffer as the pollen count goes through the roof.

The Kent coast is also bracing itself for an influx of day-trippers as they make a bee-line for the beach.

A spokesman for the RNLI warned: "The sea can look very inviting on a baking hot day but the water can still be very cold and the currents can carry unwary holidaymakers a long way from the beach. We urge everyone to take notice of any warnings."

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