Standing before a panel of judges the 60-year-old ex-pat, who has been held in custody at Silves jail since January, was read the charges of murder, desecration of a body, theft, credit card abuse and computer fraud.

Prosecutors accuse him of having murdered Brenda Davidson, who was 12 years his senior, at their home in the countryside hamlet of Alcalar, Portimão, in November last year.

He is also indicted of using her credit cards and selling off her gold as well as passing himself off as the 72-year-old in emails and text messages to cover her death.

At the time he was romantically involved with a 42-year-old Portuguese university teacher.

Brenda’s body was found buried under rubble and concrete next to a swimming pool in the villa’s backyard in January this year after Portuguese police visited the property upon being contacted by their British counterparts.

The alarm was raised in the UK by Brenda’s son Dean, 42, who contacted the police after not hearing from his mother for a while.

Following his arrest in January, Jackson confessed to having buried Brenda’s body but claimed she had taken her own life.

Yesterday (Monday) he upheld that version of events; denying he had murdered Ms. Davidson Jackson said he had found her lifeless body surrounded by “very black” blood on the floor of their home after returning from a round of golf.

He stated: “I know it wasn’t me. I wasn’t there.”

Recalling how since 2009 Ms. Davidson had twice been diagnosed with cancer, for which she had been operated and was undergoing tests and treatment, Jackson alleges in recent months had told him “week after week” that she wanted the disease “out of her” and had had a series of falls in the ten days before her death.

He said when he found her he had noted Ms. Davidson had “a small cut to her neck” but didn’t call emergency services as he was in shock and not certain she was dead.

Unable to specify exactly what day he had made the gruesome discovery, Jackson said he knew it was “the weekend before Lewis Hamilton won the championships”, in November.

Brenda Davidson is believed to have died sometime between 22 and 24 November 2014.

Jackson also claimed he buried her in the garden at her request, following a pact they had made years earlier that if anything were to happen to either of them they wanted to be buried on the property “to be with their babies”, their pet animals.

He explained how he “worked all night” to make “a proper grave” for his partner.

However, Judiciary Police (PJ) detectives giving evidence at the trial told the judges no animal bones were found where Brenda had been buried and also said, in their experience, the way the body had been buried was more consistent with having been unceremoniously “dumped”.

The PJ detectives shot down Jackson’s claim Brenda’s death was suicide, saying her wounds were incompatible with self-inflicted injuries and “totally impossible” to have been suicide.

Based on forensic evidence found at the property during the investigation they affirm a violent struggle took place.

During his testimony Jackson further explained the excuses given to family and friends in the months following her death, to cover her disappearance.

He said he had made the excuses that she was overseas or had left him to give her spirit “40 days and 40 nights” to settle and be freed, a belief he claims to uphold as a Quaker, a religion to which he says he converted in the late 1980s.

Ms. Davidson’s son Dean, a former police officer himself, was at Monday’s trial, and told the judges it was his mother’s wish that in the event of her death her ashes should be scattered in the same spot where her mother’s ashes had been scattered in the UK.