Companies are rushing to test their employees for drugs despite the high costs and "infringement" of privacy, the TUC has warned.

The trade unions argue that there are insufficient legal safeguards against the use of "unjustified and degrading" testing for drugs and alcohol.

In a new report the TUC warns that the practice has doubled over the past decade.

A survey of employers found that one in eight firms tests staff for drugs, while 80 per cent would be prepared to if they felt productivity was suffering.

"No-one is suggesting that it is acceptable to be high or drunk and work, but staff who may have drink, or related, problems need help not disciplinary action," said TUC general secretary Brendan Barber.

"A policy for identifying symptoms and a programme for dealing with an employee's drug and drink problems are far more effective than random testing."