A killer was caught on tape praying to be forgiven for strangling his pregnant partners’ mother in her own kitchen, a court heard on Tuesday.

Jobless George Maben, 45, was heard begging God for mercy over the murder of Maureen Cosgrove after detectives bugged his girlfriend Lucy Rees’ Ford Focus, the court was told.

Mr Maben was heard to say he “couldn’t take it any more” and “every day she was breaking me down”, before asking the Almighty to “forgive me for what I have done”.

Anthony Glass, prosecuting, told the Old Bailey Mr Maben’s words should be interpreted as a confession to the murder.

He said: "He provides in those words the motive or reason for the killing.

“Clearly relations between the defendant and the grandmother had seriously deteriorated.

“With her out of the way the defendant could see a future for himself, Lucy, her children and the unborn baby unencumbered by any constraints imposed by Maureen Cosgrove.”

The court heard Mr Maben went out for a drink with his girlfriend after murdering the 65-year-old teaching assistant on March 24, leaving her to discover her mother’s body when they returned to the house in the afternoon.

When interviewed as a witness Mr Maben said he had been nowhere near the house before the body was discovered, but CCTV footage showed him donning a pair of gloves as he took a bus to Mrs Cosgrove’s home, Mr Glass said.

“The cause of death was asphyxia," Mr Glass told the court.

"What he did was to put a ligature around her neck and squeeze the life out of her.

“No one has seen him do it which is often the case in murder.

“The evidence against him amounts to a series of compelling facts and circumstances, many of which are not in dispute, which when taken together add up to a formidable case against him.”

The couple had been together for two years before the murder, and had been living at Mrs Cosgrove’s four bedroom house in South Way, Carshalton Beeches with two children from Ms Rees’ previous marriage.

Mr Maben had gone back to live with his own mother in St Helier Avenue, Morden after relations with Mrs Cosgrove broke down.

He had arranged to meet his girlfriend outside the local Co-op on the morning of the murder but never turned up, Mr Glass said.

Mr Maben told her over the phone he was walking to Sutton and they went shopping in town later that morning, the court heard.

Mr Glass said: “They went to Marks and Spencer in Sutton to buy some bread for his mother, and to a pub where they sat outside and had a drink.

“Lucy Rees had made before their return a number of calls to her mother’s mobile phone and to the land line at the house, but none were answered.

“One of the reasons why Lucy was phoning was because she was anxious about who was going to pick up one of her young children at the nursery school.

“It is the Crown’s case that by this time Mrs Cosgrove had already been murdered by the defendant in her own home."

Ms Rees discovered her mother lying dead on the kitchen floor after returning to the house with the defendant.

The court heard Mrs Cosgrove was fully clothed, there were no signs of forced entry and nothing in the house appeared to have been disturbed, although at least one rear door leading to the garden was open.

Fibres from Mrs Cosgrove’s top were recovered from a jacket which the defendant had dumped in an alley and he also discarded the gloves, the court heard.

Police returned Ms Rees’ Ford Focus with a bug attached after a search, leading Mr Glass said to a recording of Mr Maben asking for divine deliverance from the murder charge on the day of his arrest.

Mr Glass said Mr Maben was heard on the recording saying: “Please God help me, please God help me, for me and Lucy eliminated from all police inquiries and everything all right.

“Please God help me, God forgive me for what I have done.”

Seconds later his pregnant girlfriend got back into the car.

Mrs Cosgrove had seven grandchildren and was a teaching assistant at nearby Seaton House School and St Philomena’s Catholic School for Girls.

Mr Maben denies the murder. The trial continues.