Britain became a fertile ground for further development of the existential approach when R. D. Laing and David Cooper, often associated with the anti-psychiatry movement, took Sartre's existential ideas as the basis for their work (Laing, 1960, 1961; Cooper, 1967; Laing and Cooper, 1964). Without developing a concrete method of therapy, they critically reconsidered the notion of mental illness and its treatment. In the late 1960s, they established an experimental therapeutic community at Kingsley Hall in the East End of London, where people could come to live through their 'madness' without the usual medical treatment. They also founded the Philadelphia Association, an organization providing an alternative living, therapy, and therapeutic training from this perspective. The Philadelphia Association is still in existence today and is now committed to the exploration of the works of philosophers such as Ludwig Wittgenstein, Jacques Derrida, Levinas, and Michel Foucault as well as the work of the French psychoanalyst Jacques Lacan. It also runs some small therapeutic households along these lines. The Arbours Association is another group that grew out of the Kingsley Hall experiment. Founded by Joseph Berke and Schatzman in the 1970s, it now runs a training program in psychotherapy, a crisis center, and several therapeutic communities. The existential input in the Arbours has gradually been replaced with a more neo-Kleinian emphasis.