Victim Eleanor Ruth Chessell, from the Isle of Wight, is understood to have been working as a travel rep on the island of Madeira and moved to Alvor in the Algarve in March in an attempt to distance herself from an intimidating relationship.

The attack is understood to have taken place at around 10.20pm on Saturday night, on the EM 531-1 road, a street just a stone’s throw away from a private hospital in the area.

The village of Alvor, in Portimão, is known for being a picturesque fisherman’s village but also a hotspot for restaurants and nightlife.

The circumstances leading up to the attack are being investigated by PJ police, but indications are that it may have been incited a vengeful ex-boyfriend.

According to Portuguese media, around two litres of acid were thrown at her.

She was assisted by local fire-fighters and GNR officers before being rushed to Portimão city Hospital, and was later transferred to the São José Hospital in the capital Lisbon due to the severity of her injuries.

She was found “writhing on the floor, screaming in pain, from the burns that covered around 60 percent of her body”, the newspaper reported, but it is understood her face was unscathed.

Two of her rescuers, thought to be GNR officers, also required treatment after inhaling fumes from the acid.

The case is highly unusual in Portugal, with the last known similar attack having occurred over 16 years ago, in Leiria, when a jilted woman threw sulphuric acid at her ex-boyfriend, resulting in his death.

The incident occurred on 21 May, 2001, and the man died 23 days later from his injuries.

After an eight-year trial the woman was considered ‘unimputable’ – not criminally liable – by the court due to a psychiatric problem.

At the time the presiding judge said she was “affected by a psychiatric illness that did not allow her to have an accurate perception of her actions.”

The court ruled that the defendant be admitted to a psychiatric unit, a measure that was suspended on the condition she maintained psychiatric treatment and followed the guidelines of the social reintegration services.

She was also held civilly liable for paying the costs of the victim's hospital expenses and ordered to pay compensation to the victim's mother of around €80,000.

Portugal has a relatively low murder rate, of around 100 homicides per year, although femicide (murders specifically targeting women based on their gender, often within a context of domestic violence) accounts for around one third of those.