Police are hunting for a man who pretended he was a plumber to gain access into a block of flats and sexually assault a 12-year-old girl.

The man called the intercom of the flat, located in Canrobret Street, Bethnal Green, and told the girl he had a delivery on May 14 this year.

When the young girl, who was in the flat with another schoolgirl, let him into the block the man changed his tale claiming he was a plumber.

He told the victim he needed to fix their washing machine and entered the flat, at about 6.25pm. The girl began to grow worried and dialled 999 as the man told the schoolgirl he needed to go upstairs to use toilet.

As the victim followed him he is believed to have pushed her into a bedroom and sexually assaulted her, fleeing the flat after the incident.

Investigating officers are trying to trace a man seen on CCTV footage inside a mini cab office, who was seen leaving the block of flats around the same time of the attack.

Police believe the man in the images went to a nearby mini cab office, hired a taxi and was later dropped off at St Stephens Road, Bethnal Green.

He is thought to be of South Asian descent, specifically Bengali, aged in his 30s, with short dark hair. In the CCTV images he is wearing a short-sleeved shirt, dark trousers and is carrying a small satchel.

Investigating officer DC Sean Simpson said: “The victim has been utterly traumatised by what happened to her and we are working with her family to support her.

“We are extremely keen to speak to this man, who we believe may have information that could assist the investigation. If you are this man or you recognise him, please call me.”

A 22-year-old man from Tower Hamlets was previously arrested in connection with the incident and was later released, with no further action, police said.

Anyone with information can call on 020 8733 5999 or email dean.simpson@met.pnn.police.uk. Alternatively, you can call Crimestoppers anonymously on 0800 555 111.