Balfour Beatty is using divisive zero-hours employment arrangements for some of its lowest paid staff to work on contracts for public bodies.
Several vacancies have appeared on the government's job website for cleaning operatives to work on infrastructure and services giant Balfour Beatty's contract with West Berkshire Council, for just above the National Minimum Wage and on zero-hours contracts.
"Balfour Beatty offers a very small number of zero-hours contracts to cover a specific short term or unpredictable business needs in our services business," said a spokeswoman for the firm.
"These contracts offer a flexible way of working which suit some people and we always make it clear when we advertise what the terms of employment will be for these roles."
Balfour Beatty boasts on its website that its employees "help complex environments - commercial enterprises, schools, industrial locations, hospitals, governments and institutions - define and then realise their strategic facilities management objectives in a world that is evolving at unprecedented speed."
The Rise of Zero-Hours Contracts
Zero-hours contracts can leave staff with uncertainty over the hours they will work each work and mean they are not entitled to the same rights as permanent employees, such as sick and holiday pay.
Government Business Secretary Vince Cable is reviewing the use of zero-hours contracts in Britain, which some firms say are used legitimately in areas such as seasonal work, where they need labour flexibility in the face of fluctuating demand, or if the arrangement suits the worker's needs.
"I think for many individuals it works well. There are people who do want casual work because they've got family responsibilities or they're studying," Cable told ITV News.
"Some people have several different jobs and this kind of casual arrangement suits them well. But there are others where we do suspect that a certain amount of exploitation is taking place."
Critics of the contracts claim they are being exploited by some employers taking advantage of the system and avoid certain obligations.
There is widespread use among local UK councils of zero-hours contracts or similar "casual" employment arrangements that leave people with no cast-iron guarantee of work each week.