Thomas Egan was given cereal containing the product at the Jigsaw Nursery in Milton Keynes although his mother had told staff he was allergic to cow's milk.

The jurors found there had been a "gross failure" to give Thomas the correct food.

The verdict of accidental death contributed to by neglect could now lead to legal action against the nursery by both the local council and Thomas' parents.

It is our belief that there can be no doubt Thomas was killed due to tragic errors and failings made by staff within Jigsaw Nurseries Gordon Egan

Thomas died in hospital on 11 April 2002, less than two hours after eating breakfast.

On Monday, nursery staff admitted they had not followed strict dietary instructions from his mother Wendy but said the severity of the allergy had not been made clear to them.

Nursery nurse Crystal Norma admitted she had not read the ingredients on the packet of cereal.

Speaking after the verdict, Thomas' father Gordon Egan, 39, said the family wanted to consult the Crown Prosecution Service about bringing corporate manslaughter charges against Jigsaw Nurseries.

He said: "It is our belief that there can be no doubt Thomas was killed due to tragic errors and failings made by staff within Jigsaw Nurseries."

He said he and his wife, who is five months' pregnant, were also upset that none of the nursery nurses had expressed personal sorrow for Thomas' death during their evidence at the hearing.

Mr and Mrs Egan are considering legal action

Jigsaw Nurseries could also face legal action from Milton Keynes Council under the Health and Safety at Work Act.

Philip Winsor, the chief environmental health officer, said a decision would be made in the next four to six weeks on whether to prosecute the company.

He said officers had worked with the nursery since Thomas' death, and the company had reviewed its procedures.

"We hope that this case and the media coverage of it raises the profile of pre-school childcare to a level where everyone who will have an involvement in this area puts greater emphasis on food allergies."

The chief executive of Jigsaw Nurseries, Michael McKechnie, said both he and his staff felt "profound sorrow for Mr and Mrs Egan"

He said the company was working to make sure there could be no repeat of what was "clearly a tragedy of enormous proportions".