The centre of London is controlled by a paid Congestion Charging Zone. The zone is shown:
The vehicles shown in green are registered as exempt from paying the charge. This is because the Union Reception registers them annually, paying a £10 admin charge per vehicle (Exemption vehicles >9 seats).
The red vehicles must may the charge for every day they enter the zone. This is the responsibility of the hirer. Any fines will be passed onto the hirer.
To pay the charge, we recommend doing it online at: TFL.gov.uk