In the UK, campaigners say figures in a new report showed inmates are spending more than £7 million ($8.5 million) a year on e-cigarettes.
The amount spent in canteens has risen every year since 2019 after a smoking ban was phased in by the government across closed jails in England and Wales.
In the previous financial year, inmates spent £7,655,766 on vapes and £7,930 on e-cigarettes — a three-year high overall, according to media reports.
Prisoners have already spent £6,730,176 of their own money on vapes alone in the current period up to January.
British American Tobacco (BAT) and Manchester-headquartered Supreme Imports Ltd. were named as suppliers of the products in the data released by the Ministry of Justice (MoJ).