The introduction of The Regulatory Reform (Fire Safety) Order 2005 requires that employers or organisations providing services to the public, take responsibility for all people, including disabled people evacuating buildings safely.
Also, The Health and Safety at Work Act 1974, the Management of Health & Safety at Work Regulations 1999 and the Disability Discrimination Act 1995, place duties on you to implement effective arrangements for access and emergency evacuation for employees and visitors.
It is therefore essential to identify the needs of disabled people and where necessary, to make proper arrangements for their assistance in the event of an emergency evacuation.
This link will take you to a form, so that you may establish any particular needs a relevant person may have to enable them to safely evacuate the building.
Personal Emergency Evacuation Plan (PEEP)