Google pays women less than men at most job levels despite claiming it is a progressive place to work.

Women earn up to $15,600 (£11,800) a year less than men even though they are in similar positions, according to a spreadsheet drawn up by the tech giant’s own workers.

Female employees also earn lower bonuses than men and are awarded up to $7,100 (£5,400) less than their male counterparts.

The spreadsheet was drawn up by a former Google employee who wanted to help colleagues negotiate better salaries. The figures are likely to add to the debate about sexism in Silicon Valley - and they come after Google fired one of its senior engineers who said the gender pay gap is down to biological differences between men and women.

Despite its lofty ambitions, Google admits there is ‘more work to be done’ on equality and its own statistics reveal that women make up 31 per cent of the company compared to 69 per cent for men.

The spreadsheet revealed pay for men and women covering six bands of jobs covering everything from entry level programmers to executives.

It was self-reported by 1,200 US staff - 2 per cent of the global workforce - meaning it is not a comprehensive analysis.

But the disparities are startling and at five of the six job levels women are paid less than men.

At level one, the lowest, women earned $40,300 (£30,500) compared to $55,900 (£42,300) for men, a difference of $15,600 (£11,800), the biggest out of all employees.

At level two women earned more than men, $76,600 (£58,000) compared to $71,200 (£53,900) for men.  At level three, the entry level for technical positions, women earned $106,700 (£80,800) compared to $112,400 (£85,100) for men.

At level four women earned $125,000 (£94,600) versus $136,600 (£103,400) and at level five the numbers were $153,500 (£116,200) for women compared to $162,200 (£122,800) for men.

At level six, executive level, women were paid $193,200 (£146,300) versus $197,600 (£149,600) for their male counterparts.

For bonuses women were awarded less than men at three of the six levels.

The biggest disparity was at level six where women earned $40,700 (£30,800) in bonuses compared to $47,800 (£36,200) for men, a difference of $7,100 (£5,400).

Natasha Lamb, director of equity research and shareholder engagement at Arjuna Capital, an activist wealth management firm, said: ‘Silicon Valley has established itself as the boys’ club of the West, just like how Wall Street has established itself as the boys’ club of the East’.

Google recently suffered a backlash over a 10-page memo written by James Damore, a former engineer at the company.

He argued that biological differences between men and women are the cause of the gender gap at Google and the broader tech industry.