Minicab drivers have threatened legal action against the Mayor of London on the grounds that the Congestion Charge discriminates against people from ethnic minorities.

The Independent Workers Union of Great Britain (IWGB), which represents minicab drivers, sent a letter to Mayor of London Sadiq Khan on Friday, asking him to reverse the decision to levy the £11.50 Congestion Charges on drivers who were previously exempt from the charge.

It has given Mr Khan until March 6 to reverse the decision and the letter said if he does not do that the union will apply to the High Court for a judicial review.

The group, which includes Uber drivers, says the charge, which they will have to pay from April, is discriminatory as 94 per cent of minicab drivers are from black, Asian and other minority ethnic backgrounds.

The legal action follows seven weeks of protests by minicab drivers calling on Mr Khan to scrap the Congestion Charge with drivers outraged that black cab drivers will remain exempt from the charge.

Minicab driver and committee member of the United Private Hire Drivers branch of the IWGB, Muhamed Ali, said: “Uber drivers like myself are being squeezed.

“It is completely discriminatory that we have to pay this charge while black cabs continue to be exempt.

“If Sadiq Khan doesn’t reverse this policy we will continue to fight it in the courts and in the streets.”

The union said Mr Khan’s policy is in breach of a number of articles on the European Convention on Human Rights covering discrimination, property rights, right to a family life and ability to carry out a profession.

It has also launched a crowdfund campaign to raise £50,000 to finance the legal challenge.

The branch secretary of the United Private Hire Drivers branch of the IWGB, Yaseen Aslam added: “We hope the Mayor sees sense and scraps this policy that promises to push thousands of drivers into deeper poverty.”

A spokesperson for Mr Khan said the number of minicab drivers entering the Congestion Charge zone has gone up from 4,000 in 2003 to more than 18,000 now.

The spokesperson said: “Most other motorists, from private cars to small business owners, are liable for the Congestion Charge.

“Removing the Congestion Charge exemption for private hire vehicles is a key part of our plans to both reduce congestion and to protect Londoners from harmful emissions from polluting vehicles.”