The number of workers on zero-hours contracts has hit a record high, ahead of Labour's planned crackdown on the practice from next year.
A surge in 16-to-24-year-olds and workers not in full-time education helped drive the number of people employed on the contracts to 1.23 million in December.
Analysis by the Work Foundation at Lancaster University, based on Office for National Statistics (ONS) data, revealed that was a 91,000 increase on a year earlier.
The Department for Business and Trade (DBT) said it "will ensure people can have the security they need by giving eligible workers the right to guaranteed hours".