A 21-year-old medical student has been found dead after taking a “party drug” which the Home Office failed to ban despite warnings of its dangers.

Hester Stewart’s parents paid tribute to their “caring, wonderful girl” and attacked the government for failing to implement plans to outlaw gamma-butyrlactone (GBL) last year.

Ms Stewart, whose family were formerly members of Brighton and Hove Orthodox Hebrew Congregation, died at a house in Brighton on Sunday morning. A container of GBL was found close to her.

It mixes with acid in the stomach to create date-rape drug GHB.

The previous night she had been to an awards ceremony in the city with friends from a cheerleading team, before later moving on to a party.

Her mother, Maryon Stewart, a well-known nutritionist and founder of the Natural Health Advisory Service, said: “I am devastated. I have lost the most wonderful daughter. She was just a shining light.

“They discovered this substance in the room where she was found. We don’t know the circumstances. She would never have bought it off the internet. How she came to take it we will probably never know. I have to face up to the fact that I had the most wonderful 21 years with her as my daughter.”

The Brighton-based family, including father Dr Alan Stewart, a nutritional physician, sister Phoebe, 27, and brothers Chesney, 26, and Simeon, 17, have called for an inquiry into why the government has failed to ban GBL.

Rabbi Charles Wallach, minister of Brighton and Hove Reform Synagogue, has been supporting the family. When the funeral takes place, likely to be next week, it will be under Reform synagogue auspices.

He said: “It is so sad that this has happened. I spent an hour with the family on Tuesday. They are obviously expressing their anger towards the government.”

Hundreds of Ms Stewart’s friends joined a Facebook tribute group called In Memory of Princess Hessie.

They left messages remembering her as a “wonderful, bright and beautiful person who filled every room with light and happiness”.

One friend, who last saw Ms Stewart on Saturday night, wrote: “You were the friendliest person I’ve met and the world is poorer now that you are gone.”

In October 2000, the RSPCA recommended the then 12-year-old Hester for a bravery award after she swam through a flooded field to rescue her dogs.

Dr John Armstrong, head of biochemistry at Sussex University, where Ms Stewart was in the second year of a molecular medicine degree, said she was “outstanding and talented” and had worked as a mentor to younger students.

The Advisory Council on the Misuse of Drugs (ACMD) recommended that the government should ban GBL in August last year, but it can be legally purchased at health food shops and on the internet.

Its use as a recreational drug has increased dramatically in the past five years.

Doctors widely recognise it as more dangerous than ecstasy. It has an industrial use as a solvent and is used in nail polish remover and paint stripper. Its use as a drug is banned in the US, Canada and Sweden.

A Home Office spokesman said evidence of its misuse is low, but the government accepts there are “associated harms”.

He added: “We have not committed to ban GBL or classify it as a drug at this stage but work continues to look at how access to this chemical can be restricted to legitimate purposes. The ACMD noted that GBL has a number of legitimate uses.

“A consultation will shortly be launched with the chemical industry and the wider public before a decision is made.”

Sussex Police are investigating the circumstances around Ms Stewart’s death.