One of two 18-year-olds JFS students burned in an acid attack in Zanzibar has been discharged from hospital.

Kirstie Trup left the Chelsea and Westminster Hospital on Sunday night.

Katie Gee, who was volunteering in Zanzibar with Ms Trup, is still being treated. She is set to undergo surgery after suffering burns to 80 per cent of her right arm and 50 per cent of her torso.

Ms Trup’s burns are less severe because after the acid was thrown at her on Wednesday night she ran into the sea. Her father Marc Trup tol Tthe Times: “That completely altered the result – the salt water and the acid.”

Ms Gee washed her wounds at a public toilet, apparently using dirty water that inadvertently made her injuries worse.

There are now claims that the girls, both FZY members from north west London, could have been targeted because they spurned the advances of local admirers, who hung around the dormitories where they and other volunteers stayed.

Police on the island off east Africa have arrested two suspects and questioned six others.