On 1 October, legislation giving contractors the entitlement to the same basic employment and working conditions as if they had been recruited directly by a company comes into force. To qualify for this entitlement, contractors have to have completed at least 12 weeks in the same job, and for workers already on assignment, the qualifying period begins tomorrow.

"In the IT world, these Agency Worker Regulations are being scanned quite keenly, and employers are doing the calculations to see if they are vulnerable to claims. All the large companies we talked with have found that with their IT agency workers, they have nothing to fear," said Iain Smith, director of IT HR consultancy .

An employment tribunal can award workers up to £5,000 if a business or agency is found to have flouted the rules.

Smith said that it was helpful that the AWR does not require a permanent employee's bonus to be included in the calculations.

"The agency worker's package is compared with the employee's package (ex-bonus) and on that count IT agency workers cannot claim to be underpaid.