1.4m zero-hours contracts in Britain

The figures, from the Office for National Statistics, show a marked increase on estimates last year that ranged from between 250,000 and 1 million.

UCU said zero-hours contracts denied staff the financial security or stability to operate on a month-to-month basis and denied students continuity with their teachers.

In September, UCU released a report that showed that over half of colleges and universities used zero-hours contracts.

UCU general secretary, Sally Hunt, said: 'Without a guaranteed income, workers on zero-hours contracts are unable to make financial or employment plans on a year-to-year, or even month-to-month basis.

'The use of zero-hours and other temporary contracts in education is far more prevalent than many people realise. These contracts deny staff full employee status and key employment rights, while students miss out on a lack of continuity and often receive reduced access to staff employed on minimal hours.'

UCU will be highlighting the issue of zero-hours and other forms of temporary contracts on its Anti-Casualisation Day of Action next Wednesday (7 May).