A Hackney Homes worker will require a long course of treatment for burns, after a stranger unexpectedly poured hydrochloric acid over his head in Upper Clapton.

The 53-year old victim was mowing the lawn at the Kier Hardy Estate in Springfield Road, Upper Clapton last Wednesday afternoon when a woman threw what was originally thought to be drain cleaner at him.

Despite wearing three layers of clothing – which prevented his injuries from being more severe - he was left with burns and blisters on his head and shoulders.

The mystery substance, which is now believed to be hydrochloric acid, did not enter his eyes as he was wearing protective eyewear.

A strong corrosive acid, hydrochloric acid is an industrial chemical which is usually used to remove stains and rust from cement and plaster.

The victim was taken to an east London hospital before being moved to the specialist burns and plastic surgery centre at Broomfield Hospital in Chelmsford.

He has now been discharged but will require a prolonged and intensive course of treatment.

Det Sgt Paul Ridley of Hackney Violent Crime Unit is appealing for witnesses, and is keen to hear from anyone who saw the incident but has not yet come forward.

He added: “I would like to reassure the public that this is an isolated incident and events of this nature are extremely rare.

“The suspect was very quickly apprehended and is in custody at this time. I am not seeking any further suspects in connection with this enquiry.”

A 53-year-old woman has been arrested on suspicion of grievous bodily harm and remains in custody at an east London police station.

Police say the victim and suspect are not known to each other.

Charlotte Graves, chief executive of Hackney Homes, said: “We will not tolerate assaults on our staff and we will always take the strongest possible action against those who carry them out.

“We are working closely with police who are investigating the incident.”

Anyone with information should contact Hackney CID by dialling 101.