Most women working full-time in the UK earn less than their male colleagues. One exception, according to the most recent figures from the Office for National Statistics, is school-leavers aged 16 and 17. These women earn an average £4.85 an hour, slightly more generous than the £4.77 rate commanded by men of a similar age.

Once women turn 18, the tables are turned. Men over the age of 18 earn an average of £11.71 an hour, 12.6 per cent more than women, who earn an average hourly rate of £10.24.

It is not all bad news. This gender “pay gap” has shrunk slightly since 2005, when men earned 13 per cent more than women.

Women in full-time work earn, on average, more than £5,000 less a year than their male colleagues. The average take-home salary for a man in a full-time job is £25,800, but it is just £20,130 for a woman.

However, in a report last year from the Equal Opportunities Commission (EOC), women between the ages of 22 and 29 earned 0.1 per cent more on average than men in the UK. The flood of women into university has helped to increase their pay, with 57 per cent of students now women. Graduates are paid at least £150,000 more than nongraduates over the course of their lifetime.

The figures suggest that it is not choice of career that is costing women but discrimination in the matter of lifestyle choice as they hit childbearing age. By the time they reach 39, women are being paid 6.6 per cent less than men. That widens to 18.3 per cent in their forties.

One grey area is part-time work. Median hourly earnings in part-time positions show that women earn £7 an hour, compared with £6.85 for men.

However, comparing mean averages reverses the picture, showing men enjoying an hourly rate of £10.38 while women receive £9.12 an hour. A spokesman for the ONS said: “Both figures are correct, but they tell a different story. The mean average figure could be skewed by a few men earning very high rates for part-time work.”

The EOC says that the average woman working full-time will lose out on about £330,000 over the course of her working life – enough to cover 19 deposits on a house, pay off student loans 21 times, buy 15 new cars or pay for 29 years of childcare, it estimated.

Sarah Wootton, the EOC head of communications, said: “Three decades after the Equal Pay Act came into force, the full-time pay gap is still a shocking 17 per cent and part-time women workers earn a staggering 38 per cent less per hour than men working full time. At this sluggish rate of progress, the pay gap will take up to 20 years to finally close in the UK.”

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