Care in the community for mentally ill people may seem like a modern idea, but in fact it goes back to the Victorian era and a hospital chaplain called Henry Hawkins. As early as the 1870s, he was proposing the creation of "half-way houses between the asylum and the world" and calling for support for discharged patients to enable them to resume, in his phrase, "life's ordinary associations".

Hawkins went on to found an organisation with an army of volunteers who arranged places in family homes for those convalescing after a spell in an asylum. It then offered them continuing practical assistance, including help finding a job.

Today, that organisation is holding a conference to mark its 121st anniversary. Maca, the Mental After Care Association, has grown into a thriving voluntary organisation with 800 paid members of staff who last year helped more than 30,000 people. Its clients range from former psychiatric in-patients with severe mental problems, and people with personality disorders, to those who need less intervention but rely on smaller projects like drop-in centres to prevent them relapsing.

Even though mental health care now is unrecognisable from the old asylum days, Maca holds on to its vision of helping people in the community achieve the basics like a roof over their head and gainful employment. Its chief executive, Gil Hitchon, insists that the challenge remains as great as when Hawkins first defined his mission at Colney Hatch asylum (later renamed Friern Barnet hospital) in north London). "The original goals remain relevant as we often still don't offer people those basic requirements for leading a fulfilling life," says Hitchon.

Hitchon believes Hawkins was on the right track with his emphasis on helping mentally ill people as individuals, not an amorphous group. The churchman noted early on that many convalescent patients left asylums only to return to "squalor and wretchedness", hampering their recovery. He was also anxious about the poor employment prospects they faced. In 1871, he wrote in the Journal of Mental Science (later the British Journal of Psychiatry) that, without work, patients would soon be back in the workhouse or, worse, finish "by an uncontrollable act of violence their miserable lives".

Eight years later, he wrote a second article on "after-care", expanding on his original ideas and proposing the formation of an association to help female ex-patients. The suggestion found ready support among philanthropists and psychiatrists who felt that the asylum system, set in train by the 1845 Lunacy Act, had laid the foundations for a segregated society.

In 1879, Hawkins called a meeting of like-minded people and the upshot was the formation of The After-Care Association for Poor and Friendless Female Convalescents on Leaving Asylums for the Insane. Care in the community had its first powerful and organised advocate.

Although the high profile figures in that early organisation were men, it was women volunteers - generally the well-heeled wives of psychiatrists, philanthropists and reformers - who were the linchpin from the outset. Hawkins was made the association's first secretary but, once he had ensured his ideas had taken hold, seemed happy to take a back seat. He saw it expand its remit to take in men, but in later years suffered ill health and died in 1904. So he never lived to see the huge growth of his organisation's work during the first world war, when it was called on to care for shell-shocked soldiers.

The second world war saw another burst of activity, as Maca helped relocate long-term mental hospital patients to residential care homes to make way for injured soldiers. The experiment was an immediate success and the organisation's annual report in 1943 noted: "We think that this method of caring for suitable chronic patients is worth further exploration and development."

And develop it they did, until, by the 80s, Maca was established as one of the most experienced providers of residential care for people with mental health needs. The 1990 NHS and Community Care Act prompted further diversification and the association has doubled its staff in the past four years.

"People underestimate the amount we do," says Hitchon. "We offer everything from advocacy services and assertive outreach with difficult to engage people, to support in people's homes, employment training and work schemes. We have moved into forensic services for people in contact with the criminal justice system - and then there's the helplines, the respite for carers, the supported housing."

Maca is content to be a service provider, not a campaigning organisation. But its "let's just get on with the job" approach means that some may have overlooked its pioneering work in the past, as well as its vital role today. As Hitchon sums it up: "As far as we're concerned, community care is the only model. And it has been from day one."