A fly expert was called in to try to help with determining when a grandfather was murdered at his Medway flat, a court heard.

Steve Berry was last seen alive at about 4pm on July 10 last year and his body was discovered by a neighbour at 5.45pm on July 12.

Research entomologist at London’s Natural History Museum Dr Martin Hall said he was contacted by Kent Police in March and given insect samples and photos.

Warning: graphic details below

He was told at first that there was no obvious insect larvae present in the body.

But after a post-mortem examination was carried out, Dr Hall was informed by the pathologist that there was conspicuous infestation of large maggots around the head area.

It was critical, he said, to know the species of insect and he determined it was a bluebottle or blow fly.

The climate at the time was also important, as flies developed at a rate that was dependent on the temperature.

Dr Hall said he was able to find out from a local weather station in East Malling that the temperature on July 10 and 11 was about 24 degrees centigrade.

But he said he was given no information about the temperature inside Mr Berry’s flat at Kinross Close in Princes Park, Chatham.

“Because of the lack of indoor temperature data I could not determine the minimum time of death,” Dr Hall told Maidstone Crown Court. “When the outdoor temperature was 19, indoor would be about 22.

“I was working out the earliest time the eggs would be laid. In my conclusion I considered that I could rule out Sunday, July 12 as the time the eggs were laid.

“I thought the egg laying would have to be on Saturday, July 11, if not earlier. I couldn’t rule anything else out.”

Dr Hall said he consulted another entomologist and they both agreed that while temperature data presented difficulties, his estimate was reasonable - that the eggs were laid on July 11 at the latest.

“I have provided a time when the eggs were laid, I haven’t said when death occurred,” he added.

Dr Hall was giving evidence at the trial of Paul Campbell, 30, who denies murdering 59-year-old Mr Berry.

The body of the heavy drinker who was in poor health was discovered by neighbour Graham Fitzgerald, 46, who was originally arrested on suspicion of being the killer.

He was released from custody following the arrest of Campbell, known as Noodles, whose palm and fingerprints were found on the oven in the kitchen.

Campbell, of Farley Close, Chatham, claims he has never been to the flat.

A pathologist found Mr Berry died from a combination of haemorrhage and head injury from “multiple blunt impacts” and penetrating knife injuries to his head and face.

He had severe head injuries including a fractured skull and brain damage. There were stab wounds to the upper chest and defensive injuries to both hands.

The pathologist concluded that food tins, a Stanley knife or the broken handle of a milk pan could have been used as weapons.

The trial continues.