Two London-based charities that provide services for people with learning disabilities and mental health needs will merge at the beginning of April.
Support for Living, which operates in west and north-west London, and the Southside Partnership, located in south London, will form a group with a combined turnover of £25m and 650 staff. A name will be announced after the legal merger takes place on 1 April.
Learning disability services in the new organisation will be delivered through Support for Living and mental health services through Fanon, a division of Southside. Both organisations will retain their brands under the new name.
Aisling Duffy, chief executive of Southside and former director of development at Support for Living, will become chief executive of the new organisation.
"By joining forces we are in a stronger position to deal with the tough economic climate," she said in a statement. "I believe that by pooling people, resources and ideas, we will be able to continue to respond effectively and creatively to the demands of personalisation and the needs of the people we support and their families."
A spokeswoman for the new organisation said no job cuts were planned "as things stand" and the two charities would continue to operate from their existing offices in Balham and Ealing.
Nigel Turner, chief executive of Support for Living, is to stand down after 18 years to "pursue other interests", a joint statement from the charities said.