Union leaders have stepped up their campaign for increases in the national minimum wage for young workers after new figures showed a million students were working at the youth rate.

More than a third of students were juggling their studies with jobs but most were only paid the youth rate of £3.60 an hour instead of the adult minimum wage of £4.20, the research showed.

Local authority areas with the highest student numbers were Birmingham (71,484), Lancashire (59,132), Kent (58,203), Leeds (58,203) and Surrey (50,448), according to the report by the GMB union.

Paul Kenny, a candidate in the election for general secretary of the GMB said: "This massive army of part-time workers are leaving college with average debts of £11,000 in student loans.

"It is not fair employers should be allowed to pay them 60 pence per hour less for doing jobs identical to their older work colleagues.

The GMB is campaigning for the abolition of age rates in the national minimum wage."