Bosses are paying agency workers 1.50 an hour on average less than workers employed full time. In some cases the figure rises to 7.
A recent TUC report found that 60 percent of agency workers - over 400,000 people - have been employed by the same firm for over a year.
It singles out BT, where 97 percent of call centre workers are employed on agency contracts.
The CWU union found that agency workers at BT can earn as much as £500 a month less than workers employed directly.
Argos warehouse staff employed by agencies are on £4.36 an hour less than workers doing the same job employed directly by the retail firm.
The report shows how younger workers are more likely to be employed on agency contracts.
Some 40 percent of agency workers working for the same company for over a year are 16-35.
Industries with particularly high concentrations of long term agency contracts include banking and finance, distribution, hotels and retail.
TUC General Secretary Frances O’Grady said:
“Employers are keeping people on agency contracts to drive down wages.
“Two people working next to each other, doing the same job, should get the same wage. But bosses are exploiting a loophole in the law that allows them to pay agency workers less.
“The government must scrap this loophole now – it’s an Undercutters’ Charter.
“The Taylor Review called for agency workers to stop being treated like second-class citizens. Ministers must get on with ending the Undercutters’ Charter.”
The full report is available here: https://www.tuc.org.uk/…/f…/EndingtheUndercuttersCharter.pdf