A black female engineer challenged Google over discrepancies in how the company paid its staff last week, igniting a furore over potential discrimination.

Erica Baker, who worked at the search engine for nine years until May, assembled a spreadsheet with colleagues while she was still at the company that showed differences in how salaries and bonuses were awarded.

This was then shared through social media, with more people contributing to and analysing the data, leading to what she termed "not great things" being revealed around pay inequality.

Writing on Twitter, Baker revealed that her manager at Google regularly rejected her "peer bonuses", $150 (£96) sums that colleagues award to each other, but are ultimately subject to a supervisor’s veto.

This was despite an unnamed "white dude" she worked with having his accepted.

"His weren’t getting rejected," Baker said. "I told him mine were. He was pissed. Wanted to tell everyone what was happening. I declined."

Despite her reluctance to follow up on the issue, other co-workers at Google found out about the situation, prompting what Baker called "outrage" and "shock" at her not talking about it.

Other staff were apparently able to negotiate for more equitable pay on the back of the sheet, according to the engineer, which by the time she left is said to have included 5% of staff salaries.

This was despite hostility from management, who "weren’t happy" that the spreadsheet had been created.

"Fighting for justice and fairness inside Google doesn’t go over well," Baker later said on Twitter. "Salary sharing is only one example."

The engineer’s allegations come as Silicon Valley addresses accusations that it fails to accommodate women and non-whites in its recruiting policies.

Google, Twitter and Facebook, among others, have recently released data on the demographics of their staff, confirming the industry is skewed towards white men.

As of January of this year Google’s global staff are 70% male and 30% female.

However, 30% of its American offices are ethnically Asian, even though Asian-Americans account for less than 5.3% of the country’s population, according to the US Census.

Challenged on Baker’s tweets, Google said: "Our policy is not to comment on individual or former employees, but we can confirm that we regularly run analysis of compensation, promotion, and performance to ensure that they are equitable with no pay gap.

"Employees are free to share their salaries with one another if they choose."