The annual event looks to improve the disabled customer experience, by encouraging businesses to increase their knowledge and understanding.
The day begins with an 8am production at Piccadilly, followed by a celebration in Canary Wharf attended by representatives of government, business and the disability community.
Jonathan Drackett, business partnerships executive for Purple, said: “It is key that we all recognise the importance of accessibility in providing inclusive experiences for everyone.
“We need to be more disability aware in order to build disability confidence. Awareness and education is therefore essential in order to drive the Purple Tuesday mission.
“Organisations need to ensure that they are providing opportunities for training and development for their people so that they can deliver a good disabled customer service and create accessible and inclusive products.”
After being ignored by shop staff with questions directed to his non-disabled partner, Mike Adams OBE set up the charity.
With 70% of disabled people not returning to businesses after poor service, Adams vowed to change the experience.
Purple has now grown to a global social movement.
Events will also take place today in Edinburgh, Berlin, Dubai, Karachi, Kuala Lumpur, Hong Kong, Minneapolis and New York.
Drackett said: “The movement recognises that every organisation and country is at a different stage of their disability inclusion journey.
“Learning from others is a great way to accelerate the pace of change needed.”
As well as today’s events the charity offer training through their Purple 365 brand.
Purple 365 is training resource which gives staff access to monthly disability materials through an online resource portal.
Companies which partner with Purple include Boots, Zurich and Standard Chartered.
However, organisations wishing to demonstrate their commitment to improving the disabled experience can sign up to Purple Tuesday for free.
As 17% of the global population have a disability, the charity only asks for a commitment to improving accessibility.