THE number of people on zero-hours contracts has risen 100,000 in just a year, creating a “nightmare for workers,” TUC general secretary Frances O’Grady said yesterday.

According to the Office for National Statistics (ONS), 801,000 workers — 2.5 per cent of the British workforce — were on zero-hours contracts in the quarter to December 2015, up from 697,000, or 2.3 per cent, in the same period of 2014.

TUC research showed that average weekly earnings for zero-hours workers were £188, compared to £479 for permanent workers.

Two-fifths of zero-hours workers earn less than £111 a week and so would not even be eligible for statutory sick pay.

“Zero-hour contracts may be a dream for cost-cutting employers, but they can be a nightmare for workers,” said Ms O’Grady.

“The so-called flexibility these contracts offer is far too one-sided. Staff without guaranteed pay have much less power to stand up for their rights and often feel afraid to turn down shifts in case they fall out of favour with their boss.”

Labour shadow work and pensions secretary Owen Smith said: “The scale of the crisis of insecure work under the Tories is getting worse with every passing week.

“Spiralling numbers of British workers cannot be certain where their next day’s work is coming from, making it virtually impossible to plan finances and family life.”

General union Unite assistant general secretary Steve Turner said: “This ‘treat them mean, keep them keen’ form of employment leaves people at the whim of their employer and unable to plan for the future, rent a home or get a mortgage.”

Ms O’Grady also said that leaving the European Union would mean that workers could miss out on new protections from bad contracts.