Drivers may no longer be able to pay their congestion charge by text message under plans being considered by Transport for London.
TfL says the texts are an under-used payment service and are hoping to launch a Smartphone app to replace it.
It says the app would allow drivers to check their congestion charge accounts and balances, along with expiry dates of discounts.
It is launching a six-week consultation on the plans.
Text messages currently make up 400 out of the 130,000 congestion charge payments made each day.