The gender pay gap at Transport for London (TfL) grew to 21.5 per cent last year – the only City Hall body to have seen an increase in the difference between men and women's average hourly earnings.
Last year the gender pay gap at TfL, which is chaired by London mayor Sadiq Khan, increased by 1.8 per cent from the previous year. Women earned £22.08 per hour, while men earned £28.14 per hour.
City Hall said the gender pay gap existed not because women were paid less for doing the same job as men, but because there were fewer women in senior roles.
Seven out of 10 of Khan's deputy mayors are women.
The gulf at TfL contrasts with City Hall generally, where the gender pay gap fell from 6.14 per cent to 4.82 per cent during the last year.
According to City Hall's latest report, there was a negative gender pay gap at three organisations within the Greater London Authority (GLA) – the Mayor’s office for police and crime (Mopac), the London fire brigade and the Old Oak and Park Royal development corporation – an organisation originally conceived under former mayor Boris Johnson to develop a new housing and community centre in west London on the back of the arrival of the HS2 project and the Elizabeth Line.
The report comes as Khan launches an online programme to help employers in the City tackle the gender pay gap.
Khan's programme aims to grant women more access to networks, contacts and opportunities that can land them in more senior positions.
All of the GLA bodies have also been required to publish their action plans on tackling the gender pay gap.
Khan said: “As mayor, I am determined to do everything in my power to address the gender pay gap that has existed unchallenged and hidden away for far too long.
“The data we have published today paints a varied picture. It does not make for comfortable reading but if we are to correct this injustice we must continue to highlight the gaps and the need for action."
Staynton Brown, director of diversity and inclusion at TfL, said: “Gender equality is something that we take very seriously. We are working hard to make our organisation more representative of the city that we serve, but we realise there is much more work to do.
“We have made progress with an increase in the proportion of women within our organisation, including in senior management roles. However, we know we need to go much further and that’s why we are working hard to tackle the gender pay gap head on by continuing to improve our recruitment and hiring processes as well as encouraging more young women and girls to consider a career in the transport industry.”