Jailed sex offenders are being trained as window cleaners.
Prisoners are taught tricks of the trade including safety advice about climbing ladders.
The idea is to help them get work when they are released.
But critics fear it could put unsuspecting customers at risk.
A prison source said: “Giving sex offenders free rein to climb ladders and look through windows when they are released is asking for trouble.
“Whoever came up with this plan has obviously not thought it through properly.”
The course is being run at Stafford jail, which specialises in preparing convicted perverts for release.
Lags can spend three weeks learning how to clean windows as part of a course in industrial cleaning.
They are also offered tuition in bricklaying, plastering, carpentry, and painting and decorating.
Last night the Prison Service said only selected inmates were allowed to take part.
A spokesman added: “The course is entirely internal and at no point do offenders leave the prison.”
