A man has pleaded guilty to the murder of a colleague whose dismembered head was discovered in a field.

Stephen Marshall (38) yesterday changed his plea and admitted killing Jeffrey Howe, three weeks into a trial.

The severed remains of the kitchen salesman, from Southgate, north London, were discovered across Hertfordshire and Leicestershire last year.

His disfigured head was found in a field in Asfordby, near Melton.

The 49-year-old became known as the "jigsaw man'' after a series of macabre finds.

Marshall had previously admitted dismembering Mr Howe and disposing of his body parts, but denied murder.

He was on trial alongside his girlfriend Sarah Bush (21), of Pickard Close, Southgate, who still denies all charges.

Yesterday, Marshall, of Ayot Path, Borehamwood, stood in the dock in a baggy grey shirt and when the murder charge was put to him for a second time, he replied: "Guilty, my Lord."

During the trial, the court heard how he and Bush had moved into Mr Howe's flat, stole his food and refused to leave.

He was involved in what prosecutor Stuart Trimmer QC described as a "determined" plan to hide his disappearance while making use of his money and property.

Marshall stabbed Mr Howe to death and dismembered him in his own home on March 8 or 9 last year.

He and his girlfriend, a mother-of-two, began to use their victim's bank account as soon as they had killed him, Mr Trimmer said.

They sold his car, a Saab, on eBay and began spending his money on clothes, shoes and food.

Mr Howe's remains were discovered by members of the public between March 22 and April 11.

The police investigation was sparked when a left leg, severed at the thigh, was found wrapped in blue plastic close to a road in Cottered, Hertfordshire.

His left forearm, right leg and torso were found at different rural locations over the following two weeks.

On March 31, his head was discovered in a field close to Asfordby cemetery.

The flesh of the scalp and face had been removed and the ears, tongue and parts of the neck had been cut away.

Both his hands are still missing.

A witness said Marshall had boasted to her of his ability to butcher a human corpse.

He told the woman, who cannot be identified for legal reasons, he had cut up bodies for a criminal family in London – the "Adams" family – disposing of them in plastic bags and burying them, she said.

He told her he started taking cocaine to deal with the nausea it caused him, and became addicted.

Mr Howe and Marshall sometimes went drinking together.

The court heard Marshall had lived a "playboy lifestyle", paying thousands of pounds for prostitutes and taking large amounts of drugs.

Friend Andrew Sangers told the court he knew Marshall had criminal connections and that he was a "loveable bad guy''.

He said: "He was a very popular man and a lot of people like him."

At the start of the trial, Marshall pleaded guilty to two counts of perverting the course of justice and one of intending to prevent a coroner from holding an inquest.

After he admitted the murder charge yesterday, the jury of seven men and five women formally returned a guilty verdict. The trial was adjourned until Monday.