A man killed his 160kg (25 stone) father and then carefully dismembered him and neatly packaged the body parts in plastic storage boxes which he used as a TV stand, a court has heard.

Nathan Robinson used a Stanley knife, saw and hacksaw to cut up the body of taxi-driver William Spiller, 48, at the flat they shared in Bournemouth, Dorset.

Robinson, 28, has denied murder in his trial at Winchester crown court but admitted manslaughter on the grounds of diminished responsibility.

Nigel Lickley QC, prosecuting, told the jury Robinson killed his father in May 2013 following an argument over money. Hours later, the occupant of the flat below noticed a “pink liquid” dripping through the ceiling of his bathroom.

The prosecutor said this was diluted blood as Robinson cleaned up the crime scene with a steam cleaner which he had bought after killing his father.

Lickley said: “Mr Spiller was a large man – 6ft 5in, he weighed in excess of 25 stone – hence I say when his body was cut up and dismembered, it would have taken time and effort … it would have been a messy business.” He said Robinson attempted to cover up the killing and used his father’s mobile phone in the following weeks in a bid to pretend he was still alive.

The downstairs neighbour had previously heard a heated exchange of words coming from above in which Spiller said: “Do you expect me to keep subsidising you for the rest of my life?”

When he went to investigate the liquid, Robinson answered the door and was described as “very calm, just normal, very collected, there was nothing to say he had just had a fight with his dad”.

Lickley said Robinson’s actions meant his father’s body was not found until a month later after his father’s partner, Glenys Molyneaux, reported him missing to police. Lickley said: “Dorset police attended the flat. They noted strong smells and flies, alive and dead, in the hallway leading up to the property.

“They …entered and they found Mr Spiller within the bedroom area. His body had been dismembered – that is, cut up, deliberately and carefully – and placed in plastic storage boxes together with items of clothing. Mr Spiller’s head had been removed, cut off, and was found within another box within a filing cabinet in the bedroom.

“In one of the boxes was a Stanley knife with a relatively small but sharp blade, a saw and a small hacksaw – the tools, the crown say, which were used to kill and cut up the body.”

The jury members were shown photographs of the flat including the “grisly” filing cabinet with the box containing Spiller’s head inside.

The prosecutor said Robinson took at least £7,750 in cash belonging to his father and the day after the killing, went to visit friends in Glasgow where he spent up to £300 “drinking, eating and socialising”.

He said Robinson had been in debt to his father and a note written two years earlier detailed a loan of £36,000.

He said Spiller had lent his son money to go on holiday to Thailand at the same time as he needed to pay for insurance on his taxi, which led to him being in court for failing to take out the mandatory cover.

He added that Molyneaux described Robinson “as someone who could get round his father easily” and who had behaved “inappropriately” towards her.

When he was later arrested at his mother’s home in Birmingham, Robinson asked police: “Is this a joke?”

Lickley said Robinson admitted killing his father and dismembering his body but denied his murder.

He told the jury: “There is no issue between the prosecution and defence that, first, the defendant did kill his father; second, cut up his body into parts and placed them piece by piece into plastic storage boxes; or, third, he took the sums of money.

“The issue for you to resolve centres on was the defendant’s responsibility at the time of the killing diminished by virtue of an abnormality of mental function so as to reduce the crime from murder to manslaughter?”

He said that psychologists being called as expert witnesses by the prosecution and the defence disagreed as to the defendant’s mental health.

The trial, which is expected to last three weeks, was adjourned until Thursday.