A number of Welwyn Garden City residents have been evacuated from their homes after a 25-metre deep sinkhole developed yesterday.

The sinkhole developed in Martlesham, Panshanger, and the area has been cordoned off by police.

The cavern is estimated to be around three metres wide and over 25 metres deep.

Residents and nearby buildings have been evacuated as of yesterday (May 2).

Eyewitnesses believe the sinkhole appeared over the weekend and became bigger yesterday.

Welwyn Hatfield Times: The area has been blocked off by police.The area has been blocked off by police. (Image: Supplied)

People have been advised not to return to the area as it is potentially unsafe.

Welwyn Hatfield Times: Police were on the scene yesterday after residents reported the sinkhole.Police were on the scene yesterday after residents reported the sinkhole. (Image: Supplied)

Panshanger Ward councillor, Jane Quinton, said: "Please avoid going down Martlesham even to walk to the woods as it's closed off.

Welwyn Hatfield Times: Sinkhole appears in Panshanger.Sinkhole appears in Panshanger. (Image: Supplied)

"A big sinkhole has developed in the road since yesterday and nearby buildings were evacuated in case there was damage to the gas pipes - which is why the fire brigade were present and residents were evacuated."

Welwyn Hatfield Times: The sinkhole area has been cordoned off.The sinkhole area has been cordoned off. (Image: Supplied)