Two students with learning difficulties are still seriously ill in hospital more than a month after drinking a poisonous liquid during a college visit.

The students are being treated at the Princess Royal Hospital in Haywards Heath and are regularly visited by their families.

They were among six people who drank a liquid containing dishwasher fluid on a visit to Plumpton College, near Lewes, in early December.

The brother of one of the unnamed victims told The Argus his brother remained extremely ill and was finding it difficult to eat or drink. All the students are in their 20s and 30s and regularly visited the St Nicholas Day Centre in Lewes, run by East Sussex County Council.

They were using the Green Shoots building at the college, in Ditchling Road, when they drank the mixture with their lunch.

It is believed to have been mixed with orange concentrate and may have been prepared elsewhere with the help of another student.

Some of the students had severe abdominal pain and received burns to their throat and oesophagus. The liquid was fast-acting and the students began to feel the effects almost immediately.

The drink was corrosive and led to internal bleeding.

Five ambulances, a paramedic car and a decontamination unit equipped to deal with chemical accidents were called in to deal with the incident. Ambulance staff were given guidance on how to deal with the injured by the poisons unit at Guy's Hospital in London.

The patients all had learning difficulties, making it hard for ambulance crews to convey information to the students about what was happening.

As a result they became distressed.

The other four students have since been discharged from hospital.

Sussex Police initially investigated the incident but passed it on to the Health and Safety Executive (HSE).

A spokesman for the HSE said: "We were called in to investigate this incident and that investigation is still continuing."

Dishwasher fluids are extremely poisonous. Four pensioners in a nursing home in Slough, Berkshire, died after drinking dishwasher rinse bleach in a blackcurrant cordial drink two years ago.