Police are warning clubbers to watch their drinks

The un-named woman, who has since made a full recovery, suffered violent sickness and fits following the incident and had to be taken to hospital.

Police are unsure what the drug was but have now begun a campaign in the town with posters in all the pubs and clubs advising people not to leave their drinks unguarded.

"This despicable behaviour is often associated with the covert administration of date rape type drugs or ecstasy," said Inspector Daniel Moss.

"It is a very dangerous and underhand crime.

"Drugs like ecstasy are dangerous enough for those who choose to take them of their own free will, as the Leah Betts situation showed, but to spike someone's drink without their knowledge with something so unwanted and dangerous is completely evil," he added.

A police dog, trained in drug detection will be patrolling queues and the entrances to Llandudno clubs over the coming weekends.