I only recently found out about this, see below:
This is a national card that can be used to verify that the holder is entitled to one free ticket for a person accompanying them to the cinema.
To apply for the card, you will need to meet one or more of the following criteria:
a) Be in receipt of the disability living allowance or attendance allowance.
b) Be a registered blind person.
The card is valid for 1 years from the date of issue.
A processing fee of £5.50 is chargeable per card. This is to be sent along with the completed application.