Three prison officers were taken to hospital after they they inhaled second-hand smoke from the drug know as Spice at a Scottish prison.

The officers at HMP Addiewell in West Lothian inhaled fumes from the drug after entering a cell where it had been smoked on Saturday.

Spice, also known as the zombie drug for the effect it has on users, is a so-called legal high which is thought to be a growing problem in prisons around the country.

Union officials say it poses a risk to prison officers and meetings are to be held with managers at the privately-run prison.

Spice, a synthetic substitute for cannabis, was banned by the Home Office last year after it was classed as a New Psychoactive Substance.

An HMP Addiewell spokesman said: "We can confirm three staff were taken unwell while on duty on Saturday and taken to hospital by ambulance.

"We work closely with the police and NHS to tackle drugs, which are a challenge across the whole prison estate."

Steve Farrell, Scottish secretary for the union Community, said meetings would be held with management from Sodexo, which runs the maximum security HMP Addiewell.

He said: "We have been warning prison management and the Scottish Government that 'legal highs' pose a real danger to prison officers.

"Our members do important jobs in a difficult environment, and they have just as much right to feel safe at work as anyone else.

"Community will be meeting with management and the Scottish Prison Service to understand what measures will be put in place to stop this happening again."