Members of the public can apply for them through the email address: autism@met.police.uk 

The Autism Alert Card can be used by all autistic people and includes basic information such as the person’s name and contact details for an appropriate adult. The card also details information about autism and provides practical advice for the officer. 

There is also an A5 sized booklet version of the card, which goes into more detail about how the officer should communicate with the person, including how to help the person and any relevant information about them.  

See full article from Met Police.