Conservative London mayoral candidate, Shaun Bailey called for every business in the capital with more than 250 employees to sign up to a drug-testing charter – routinely checking with the results being made public. Mr Bailey said this would help to identify middle-class cocaine users, who are fuelling the “explosion” of crime among poorer communities by purchasing drugs from criminals.

Entrepreneur Theo Paphitis strongly criticised the proposal with Paphitis calling the proposals a “crackpot idea” and “the only people the proposed plans would “punish” would be employers.”

Considering these different points of view, should employers think about drug testing their employees?

As an employer, you will want to feel assured that your staff can be relied upon to perform their duties safely at work, something which may be jeopardised if they are under the influence of recreational drugs. To address this, drug testing can be used. However, it should only be restricted to specific circumstances.

Under the Health and Safety at Work Act 1974, employers have a duty to protect the safety of their workplace, staff or any third parties, which includes ensuring staff are not working under the influence of drugs. The best way to do this would be to create a workplace policy in which you can outline your zero-tolerance approach to staff when it comes to working while under the influence. This policy could also allow you to reserve the right to randomly drug test employees, however, to avoid claims of unnecessary breach of privacy, you should ensure such tests are only carried out in appropriate circumstances.

When conducting random drug tests, it is vital to ensure the use and application of the tests are justified. Tests will generally be considered justified when they are a regulatory requirement or involve critical safety roles such as driving or construction. It would be best if you were also certain that any tests provide significantly better evidence of impairment than any less intrusive measures. As prior consent is required, you should make sure this is obtained. Refusals can be dealt with as a disciplinary offence if contracts allow for this.

Requests to drug test employees who work in lower-risk roles, such as office staff, will generally be considered less appropriate. Yet, it is possible to do so providing contracts are worded appropriately. However, before doing so, you should weigh up the potential negative ramifications this could have, specifically the risk of alienating and offending your workforce.

It is also essential that individual employees are not singled out for testing due to past criminal convictions or a protected characteristic, as this could lead to claims of bullying or discrimination. With this being said, if you have reasonable, valid concerns that an employee has attended work under the influence of drugs, then a test can be justified under these circumstances.

You must also ensure your approach to drug testing complies with the data protection principles relevant to special category personal data. Third parties are often used to assist in the drug testing process, and these must be appropriately accredited and use the appropriate scientific methods.

The key when it comes to drug testing employees is to ensure the act of testing is both reasonable and appropriate under the circumstances. Providing this is the case, and you have the robust contractual provisions in place, you should have sufficient authority to carry out the tests.