St Stephen's AIDS Trust was originally established by a Deed of Trust dated 25th February 1991. The organisation became a formal partner of Chelsea and Westminster NHS Foundation Trust on 1st April 2004. The partnership is established by a formal agreement set out in a Memorandum of Understanding which has been an enduring success.
The Charity was incorporated as a company limited by guarantee on 22nd January 2010 and registered as a Charity on 8th February 2010. It is governed by its memorandum and Articles of Association. The charity company took over the activities, assets and liabilities of the unincorporated charity with effect from 1st April 2010. On 19th December 2011 the Board of Trustees agreed new Articles of Association for the Charity, including a range of new organisational and governance infrastructure, which was formally adopted in January 2013.