Transport for LondonVolunteers needed for travel support trials
The size of a credit card, it is designed to give disabled people greater confidence to ask for help if they need it.
Showing the card will alert members of staff that the passenger may need extra support.
Chris Upfold, London Underground's accessibility and inclusion manager, said: 'This new card is designed to make life easier for people who may need extra help.
'For instance, if a journey is disrupted for any reason, the customer can use their card to indicate to staff that they would like extra assistance or support.
'The card will show staff how best to help that individual customer by, for example, taking the customer to the right platform, or taking extra time to explain alternative routes.
'This will improve the confidence of disabled people travelling in London and mean that more people can use the transport network that so many of us take for granted.'
TfL is working on trials of the card with disability charities, but more volunteers are needed - particularly from the Stratford, Willesden Junction and Wimbledon areas.
If you would like to take part in this trial, email Kathryn Lyon at accessibility@tube.tfl.gov.uk
