What is a sinkhole, what happened on the M25 and what causes them?

11 June 2019, 11:34

What are sinkholes and what causes them to form?
What are sinkholes and what causes them to form? Picture: Getty

After a bout of bad weather, a series of sinkholes have emerged across the UK - namely on the M25 and in Sheringham High Street.

While sinkholes are rare, they can - and have - occurred in the UK.

But what are they exactly and what causes them? Here's everything you need to know.

What is a sinkhole and what causes them?

A sinkhole is a depression in the ground - and can also be referred to as a cenote, swallet or doline.

It is where the land collapses, leaving a large hole on the surface.

They usually occur when the rock beneath the surface is dissolved by water, but they can also occur when the land is parched.

The most commonly affected areas include areas of land with limestone or chalk foundations.

While they're very common in the States, they do form in the UK from time to time.

What happened on the M25 and on Sheringham High Street?

Two sinkholes appeared on the M25 motorway around 11.30pm on 10 June, 2019, causing major traffic and delays.

Kent Police said they were responding to a nearby traffic incident near Sevenoaks when they discovered the sinkholes.

Road diversions were still in place this morning due to a "serious road defect".

Repairs to the road were carried out overnight, but there was another incident on the M25 that prevented the road from being reopened.

A spokesperson said: "Kent Police were called at 5.17am on Tuesday 11 June regarding a distressed man on a footbridge above the motorway near Swanley.

“As a result both carriageways of the M25 were closed."

Meanwhile, in Sheringham High Street, a 26ft hole emerged on 25 May. Anglian Water are currently investigating the sinkhole, but fear repairs could take all summer.

Local businesses are worried about the economic impact of the road closure and wait to hear what will happen in the way of insurance.

The local council said the High Street would still be open to shoppers and pedestrians.

Where else has been affected in the UK?

Areas in the UK that are more prone to sinkholes include Dorset, Hampshire, the Chilterns, parts of Wales, Yorkshire and the Peak District.

This is down to the levels of chalk and limestone in the areas. Sinkholes are, however, extremely rare in the UK.