A retired fireman bludgeoned his own son to death with a scaffolding pole in a "cold-blooded" bid to win custody of his granddaughter, a court heard.

Colin McSweeny, 59, of Parry Road, lured Shaun McSweeny into the garage of their South Norwood home and murdered him in a "deliberate but desperate" attack on November 20, it is alleged.

He killed Shaun after being "devastated" to learn he planned to move out of family home with his five-year-old daughter, a jury was told.

He then left the 24-year-old's body while he spent the evening with a police officer friend just metres away in their living room, a prosecutor told the Old Bailey this afternoon.

Later that night Mr McSweeny allegedly tried to dump his adopted son's body in the River Thames at Deptford Wharf but was spotted and arrested.

He was found with his son's body wrapped in a tarpaulin in the boot of his car, the court heard.

Crispin Aylett QC, prosecuting, told the jury: "This case is as terrible as it is tragic. No doubt you will find this hard to take in. 

"The prosecution allege that the defendant killed his son deliberately. It may have been hastily conceived and ill thought-out but it was nonetheless done deliberately.

"Sadly, in his own mind the defendant had every reason to wish his son dead: he and his wife could carry on looking after their beloved grandchild without any interference from the girl's father."

The court heard Shaun's plans to move in with girlfriend Laura O'Donnell put the couple "on a terrible collision course" with Mr McSweeny and his wife Gloria, who adopted Shaun when he was six. 

Shaun's mother and father were said to be highly critical of his parenting skills and felt their granddaughter should stay with them.

Mr McSweeny kept a database of photographs and videos showing the messy state of Shaun's bedroom "as ammunition for the custody battle that would follow", the jury heard.

On Mr McSweeny's computer, police also found footage of Shaun returning home drunk in the early hours of the morning and leaving the house to visit his girlfriend, with audio commentary from his parents criticising him.

But Mr Aylett said: "She was Shaun's daughter and there was nothing the defendant and his wife could do - at least not legally."

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Flowers laid outside Shaun McSweeny's home after his death

Two days before Mr McSweeny was due to move with his daughter, born to an earlier girlfriend when they were both teenagers, his father repeatedly stuck him with a scaffolding pole. 

Shaun suffered a fractured skull and brain damage and died soon after, the court heard. 

When police searched the garage, they found the weapon wrapped in cling film and tarpaulin laid on the floor.

He is said to have then moved Shaun's van, which the 24-year-old drove while working repairing windscreens for Autoglass, to make it appear he was out. 

He then entertained an off-duty policewoman who was visiting his wife by making tea and telling "funny stories", the court heard. 

In the early hours of the morning, Mr McSweeny is said to have tried to dump his son's body in the Thames in Deptford. 

A witness saw a white-haired man dragging a body out of his car boot by the ankles to the waterfront and trying to lift it over the wall, before pulling it back to his car.

Mr Aylett said: "It would seem that the tide must have been against the defendant."

An officer called to the scene passed Mr McSweeny's 4x4 and pulled him over. Inspector Simon James asked the defendant what he had in his car and Mr McSweeny replied: "A body."

Officers found Shaun's body lying on a heavily-bloodstained tarpaulin in the boot, while a search of Deptford Wharf uncovered blood traces on the wall, a piece of tarpaulin, one of Shaun's shoes and a trail of coins and buttons.

Mr Aylett told the jury: "Having murdered his son, the defendant intended to dispose of his body in such a way as might mean that it was never found or, if it was, that Shaun's death could not be linked to him.

"In the event, of course, getting rid of the body turned out to be rather more difficult than he had imagined and the plan quickly unravelled.

"Nevertheless, that does not detract from the cold-blooded way in which the defendant murdered his son."

Mr McSweeny's wife Gloria, who adopted Shaun with her husband when he was six, was also arrested the morning after his death but never charged.

Mr McSweeny denies murder and claims he killed his son in self-defence.