An NHS worker who was targeted and spiked while enjoying a private work party has warned others to stay alert this Christmas.

Lauren McLean, 21, of Thorpe St Andrew, remembers a stranger who gained unauthorised access to the event draping their arm over her shoulders and offering to hold her drink.

Half an hour later, she was being treated by A&E colleagues at the Norfolk and Norwich University Hospital after she collapsed unconscious in a city pub.

She was off work for two weeks as a result of the suspected spiking.

The victim, who had seizures following the incident, was found unconscious in the toilet by medical colleagues who carried her into her dad's car to drive her home around 11.45pm on November 1.

Miss McLean had managed to call her dad just before she collapsed, having sensed she was in danger.

An ambulance was then called to take her to hospital due to deterioration on the way home.

She said: "You do not expect to go to an A&E party and end up going to A&E yourself at the end of it.

"My parents are petrified and have still not recovered from it. My sister is not a big drinker anyway but she has said she is never going out again. She doesn't think it's worth it."

Ahead of the Christmas party season, Miss McLean has advised people to have a back-up plan on a night out in case something sinister happens with relatives being informed beforehand.

Miss McLean has purchased her own drink-spiking prevention scrunchie online called a NightCap, which costs around £9 in addition to her own metal straw to go with it.

The NHS worker recalled the stranger trying to follow her into the toilets.

She said the suspected spiker and another person had also offered her colleagues drugs and to hold their drinks for them while they went to the toilet that night.

She warned people to stay well-clear of strangers, adding: "Before it happened I always thought it would never happen to me.

"But all my friends who are still going out clubbing are never offered drink stoppers in venues - it is reassuring to get your own."

The incident was reported to Norfolk Police but it is understood the investigation has closed due to a lack of CCTV evidence.

A police spokeswoman said: "We can confirm we have received a report of spiking at a business premise in Tombland in Norwich on November 1. The incident happened sometime between approximately 8pm and 11.30pm.

"Officers investigating the incident conducted a number of lines of enquiry including CCTV opportunities, speaking with the venue staff, and forensics.

"It has since been established that the enquiries have been exhausted and the investigation has been closed. If we receive any further information we would review this."