A union is threatening strike action if the two social workers in the John Smith case are disciplined.

Dave Pamely and John Barrow are suspended and The Argus understands they are facing the sack.

Yesterday, the local government union Unison insisted the boy's death was not their fault and blamed too few staff and increasing workloads.

City branch secretary Alex Knutsen said: "If disciplinary action is taken against our colleagues then Unison will ballot its members for strike action.

"We will simply not accept responsibility for this tragedy being placed on individual workers.

"The service is managed by the council and it is the council that must recognise what has occurred, its responsibilities and how it must be put right."

He claimed 20 frontline social worker posts were axed in early 1999, against Unison's advice.

One of John Smith's social workers had told his managers his caseload was "overwhelming", he was having to prioritise action on cases and was unable to work in anything like a normal way.

Mr Knutsen said social services in Brighton and Hove and nationally were in crisis.

He said: "The city council needs to recognise this as a fact and not try to cover the vast gaps in resources by continuing its previous policy of loading ever more work on ever less staff. Bluntly, to achieve a high-quality service where the children we care for are safe, the Government needs to properly fund our social services.

"Unison members in Brighton and Hove social services will no longer tolerate a situation where they are so under-resourced that they cannot guarantee a further tragedy such as this will not happen again. They will defend their colleagues in this case and they will demand the council properly fund social work services."

Allan Bowman, strategic director for social care and health with Brighton and Hove City Council and chairman of the Brighton and Hove Area Child Protection Committee, said: "I take the view this was a child who was in my care and he should be alive and enjoying a healthy future and he is not.

"We have to accept responsibility. We took a child into our care to do better for him than his own parents and in all circumstances we let him down. We must make sure it never happens again."

The McWilliams had pulled the wool over the eyes of professionals.

It was impossible not to feel angry: "We do not deny responsibility and failures and we should never have let a couple like this have the child.

"It is a sad fact that within society there are people who can and do cause harm to children. These people can be devious, manipulative and plausible. This case has shown the McWilliams to be such people.

"They succeeded in drawing experienced professionals into their view of events, which meant the vital questions were not asked and further medical advice was not sought.

"All the agencies involved have learned lessons and are implementing major improvements in the way we look after children in our care."