A drug and alcohol-testing provider recently carried out random workplace drug tests and pre-employment drug tests on behalf of 856 UK employers (with drug misuse policies in place). According to Concateno, the tests showed that at least one in 30 employees has illegal drugs in their system at any point in time, which equates to nearly one million people across the UK workforce. The tests showed that from 2007 to 2011 there has been a 43% increase in UK employees testing positive for drug use. It is an offence under the Misuse of Drugs Act 1971 for any person to knowingly permit the production, supply or use of controlled substances on their premises, except in specified circumstances. Employers can therefore break the law if they knowingly allow employees to take part in drug-related activities on their premises. In order to limit the level of drug use amongst employees, employers should adopt a substance misuse policy, in consultation with their staff, which sets out how the organization expects employees to behave.