By looking backwards not forwards, Ron Shields misses the point by criticising single-focus mental health trusts (Letters, 23 April). The issue is not whether combined or single-focus trusts have been more effective in the past, but what will work best in the future. Above all else, mental health services will need strong, visionary and effective leadership in a new NHS dominated by the twin agendas of primary care and acute services. Both combined and single-focus trust models can support strong leadership, but the former will only do so with the fortuitous presence of certain outstanding individuals at board level. By contrast, the whole purpose of single-focus trusts and their boards will be the promotion of mental health services, and while that does not guarantee effective leadership it makes it a darn sight more probable.

Equally, Mr Shields barks up the wrong tree in suggesting that single-focus trusts will be isolated from the rest of the NHS. The whole point about mental health services is that they can only be delivered effectively through partnerships, not just across the NHS, but with a host of other agencies.

My own (single-focus) trust has service partnerships with a couple of dozen other organisations (social services, housing departments, housing associations, probation services, voluntary agencies, black groups, acute trusts) as well as delivering services in 24 local GP practices. Our effectiveness in these partnerships derives from our focusing on what we do best (delivering mental healthcare and support) while our partners do whatever it is they do best. This is not isolation but integration.

Peter Reading, Chief executive, Lewisham & Guy's Mental Health trust.