BUILDING REGULATIONS 2000 | APPROVED DOCUMENT M : 2004 
Any new or substantially refurbished building must be built so as to allow the same rights of access to disabled people as able bodied people. 

Suitable sanitary arrangements must be provided for ease of access and use 

Washroom facilities for these commercial premises must be provided as described in Approved Document M Section 5 of the Building Regulations. 

DISABILITY DISCRIMINATION ACT : 2005 
The Disability Discrimination Act 2005 requires ‘that all suppliers of services, goods and facilities to the general public must remove all physical barriers where deemed reasonable’. 

So where toilet facilities are offered reasonable provision for everyone, of all levels of ability including wheelchair users, must be made.

BS8300 : 2009 
British Standard BS8300:2009 - Design of Buildings and their approaches to meet the needs of disabled people, Code of Practice. This British Standard explains how the building can be designed to anticipate and overcome restrictions that prevent disabled people making full use of the premises and their surroundings.
BS8300 should also be followed for guidance on good practice in the design of buildings.