The British child, who was on holiday with his mother and grandparents in Cambrils on the Costa Dorada, fell 16ft after climbing on a plastic chair, it was claimed.

He was flown by helicopter to the Vall d'Hebron Hospital in Barcelona with head injuries, according to the manager of the Best Cambrils Hotel where the family were staying.

It is believed he sustained a fractured skull, but his condition remains unknown.

The manager of the 400-room hotel, who refused to give his name, said: "The accident happened on Tuesday afternoon. Our staff were first alerted when they heard screaming.

"He was flown 100km to hospital in Barcelona with his mother. His grandparents have also gone there to be with him. They told me he was in a critical condition.

"I do not know how he is doing now and I do not know where in England the family are from."

Police based at the beach resort could not confirm that they were investigating.