Over a million individuals in Britain report to work with drugs still in their system, suggests study.
Figures from a drug-testing firm have revealed that around one in 30 employees tested at work last year had taken narcotics, with the most commonly-used drugs being cannabis, opiates and cocaine, the Daily Mail reported.
Drug-use among employees was up 43 per cent from 2007, rising to 3.23 per cent of the workforce last year.
The country's most senior police officer told employers earlier this year to consider introducing compulsory regular drug- testing as a condition of employment.
Bernard Hogan-Howe, the Commissioner of the Metropolitan Police, said many affluent workers are working in roles, including surgeons, teachers and drivers, where cocaine use risks lives.
The latest figures come from an analysis of 1.7 million tests carried out by the company Concateno for 856 UK employers, including public transport firms, freight hauliers and the emergency services.
"These are conservative figures when you consider how many companies do not have a screening programme in place," laboratory director, Dr Claire George, said.
The latest study found the most likely age group to test positive for Class A drugs were 25 to 34-year-olds - not the under-25s - as they were likely to have more access to disposable income.