The call follows an Adverting Standards Agency ruling that one site – paylondoncongestion.co.uk – was ‘likely to lead consumers to believe that the web page was an official method of paying the London congestion charge and was affiliated with TfL’.

The ASA investigated and upheld three complaints relating to the site misrepresenting a link with TfL and not making clear the fees it levied. The ASA has told the site that its adverts – including the sponsored search ads on Google – must not appear again in their current form, must make clear the site has no affiliation with TfL and the company must make their fees clear at the point at which the customer enters the site.

The website is just one of a number that offer to pay the Congestion Charge on behalf of drivers but are not official payment channels and charge motorists a up to a £6 premium for the same services that TfL provides for free. There have also been a number of cases where these unofficial sites have failed to pay the Congestion Charge on behalf of their customers, resulting in drivers receiving a Penalty Charge Notice (PCN) from TfL for non-payment of the Congestion Charge. Such sites have also accepted payments from customers when the Congestion Charge is not in operation.

TfL adds that around 1,000 people per day may unwittingly use unofficial sites to pay the charge.

London's Transport Commissioner, Sir Peter Hendy CBE, has also now written to the search engine Google, calling on the company to take note of the ASA ruling and to take action against the misleading unofficial sites. Some of the sites currently pay Google so that links to them appear when people search for how to pay the Congestion Charge. TfL is calling for Google to remove these adverts and not to accept them in the future.

Garrett Emmerson, TfL’s Chief Operating Officer for Surface Transport, said: 'We welcome the ruling by the ASA and are using this opportunity to again raise awareness of these unofficial Congestion Charge payment sites. Customers should take care when paying the Congestion Charge online and only use the official site -www.tfl.gov.uk/cc – which is a quick and easy way to pay, and avoids any unnecessary charges.

‘TfL will be taking steps to seek to ensure that unofficial websites and search engines who allow them to advertise are not misleading the public.

‘We will continue to pursue these avenues but in the meantime we urge motorists to take care and only use TfL’s website.’

Customers can avoid paying via unofficial websites by registering with TfL for the automatic payment service, CC Auto Pay, which provides a reduced daily charge and bills the customer’s debit or credit card monthly. 

Earlier this month TfL announced a consultation on a number of changes to the Congestion Charge, including raising the daily rate 15% in a move to ensure Congestion Charge remains a deterrent to unnecessary journeys in central London.