From thestage.co.uk:

A type of revolver that fires blanks and which has been used widely by theatres and film production companies has been made illegal.

It is now illegal to possess, supply or transfer an Olympic .380 BBM revolver, which also goes by several other names, including Bruni Olympic Revolver – Blank Firer, Olympic 9mm, Olympic .380 and Olympic .38.

According to a statement issued by the Metropolitan Police, the reclassification is because the revolver can be easily converted into a lethal weapon. Following an independent test carried out by the Forensic Science Service, the gun has been identified as being “readily convertible” under the provisions of the Firearms Act 1982.

There is currently an amnesty for those who possess these pistols to hand them in to police stations before midnight, June 4 without facing prosecution. All police forces in England and Wales have been notified of the amnesty.

A five-year mandatory prison sentence will apply to those in possession of the revolver after the amnesty period.

Importation of these revolvers into the UK stopped on March 24.