Call to prosecute employers who do not pay apprentices the minimum wage
Figures which show an increase in the proportion of apprentices not paid the full minimum wage they are due are "shocking", campaigners say.
A government survey reveals that 18% of apprentices were paid less than the minimum wage rate they were entitled to in 2016, up from 15% in 2014.
The top five offending sectors have all seen increases in non-compliance:
:: Hairdressing: 46% paid below NMW in 2016, up from 42% in 2014
:: Childcare: 27% paid below NMW in 2016, up from 26% in 2014
:: Construction: 25% paid below NMW in 2016, up from 21% in 2014
:: Electrotechnical: 23% paid below NMW in 2016, up from 17% in 2014
:: Health, social care and sport: 17% paid below NMW in 2016, up from 12% in 2014
TUC general secretary Frances O'Grady said: "It is shocking that so many apprentices are being cheated out of the pay they have earned.
"Bosses in hairdressing and childcare are the worst offenders, meaning that thousands of young women are being denied their legal rights.
"Workers at the start of their working life are entitled to be paid the national minimum wage.
"Ministers must urgently find the employers responsible for breaking the law, name them publicly and prosecute them."
Young Women's Trust chief executive Dr Carole Easton said: "It is shocking that even with the very low levels of minimum pay permitted for apprentices so many employers still break the law.
"Young people doing an apprenticeship face the same living costs and bills as other employees, which is why the minimum wage for apprentices needs to increase.
"Government should also invest in enforcement systems to hold employers to account.
"It is striking that sectors like hairdressing are most affected by employers paying under the minimum wage.
"More than nine in 10 hairdressing apprentices are women and this once again shows how little employers value so called "women's work".
"We need to ensure all apprentices get better pay whilst also supporting more young women to consider apprenticeships in traditionally male-dominated sectors such as engineering, IT and construction which tend to be better paid and offer better career prospects."
A Government spokesman said: "It is every employer's responsibility to know the law and there is no excuse for paying apprentices less than minimum wage rates.
"The Government is determined to ensure the UK's lowest paid workers get what they are owed.
"Last year HMRC identified almost £11 million in back pay for more than 98,000 workers and this year the Government has committed a record £25.3 million to minimum wage enforcement."
Shadow business secretary Rebecca Long-Bailey said: " That there are apprentices who are paid less than minimum wage is unacceptable. That the practice is on the rise is shocking.
"The Government has not taken sufficient steps to enforce payment of the minimum wage. Employment rights are only safe in Labour hands."