SOCIAL workers in one London borough are now brushing up on the cycle of grief, on the turbulent pathway of loss. But not because any one has died.

Not all children are born healthy in mind and body: some have a high level of need in daily aspects of living. And, as one social worker told me recently, it is hardest when the child gets to around ten or 11 years old.

"The care teams couldn't understand why parents suddenly started speaking of their frustrations when the child reached ten," he told me. "They'd been able to cope before; they seemed to be getting on with things. And then they weren't. It was like the full nature of the truth hadn't sunk in until then."

All parents know the challenges as children pass through the teenage years. But it is particularly harsh for those where there is a high level of need. "They can't now be left with friends," the social worker said, "which can often be a lifeline. They're not cute any more: they're speaking up for themselves, making demands."

And then, for the parents, there is the issue of mortality - their own. They start looking ahead down the years, and wondering how long they will be able to do what they do. They have managed so far, but the energy begins to wane, and what then? And who will be doing what they do for their child when they die? And, of course, their child's 18th birthday can focus the mind.

"Parents can get very upset and insecure when their child hits 16," the social worker says. "They can see the end of the care road. Once a child reaches 18, they come under adult services, where there's a lot less provision. Marvellous things are still done by the social services. But some parents have to be told that they won't reach the threshold for ongoing support after 18 - care they've relied on since the age of four."

And the grief? The grief is for everything lost - for a life they and their child have not been able to live, or will not be able to live. It isn't going to get any better. The famous cycle of grief must be played out in some manner: shock, denial, anger and guilt, bargaining, depression, and perhaps acceptance.

It is hard to handle a sense of loss when no one has died, with no public funeral to help, and no grave to sit by. This perhaps goes some way to explaining the outpouring of grief at the death of Diana, Princess of Wales, in 1997. There was genuine sadness at her death in a French underpass.

But, as the days passed, the sadness became something else: a scream and a rage of flowers around Kensington Palace, as if every unnamed sorrow and loss were somehow being exorcised. There's a grief cycle in life, as well as in death.