He added: “It was only through the quick actions of the police carrying her out of the house to the waiting paramedics, and then the treatment she received from them and the doctors at the hospital – restarting her heart when she went into cardiac arrest and operating upon her to stem the blood loss – that she survived, albeit with severe and life-changing injuries.

“The same, unfortunately, cannot be said for Sir Richard. As the police went around the house carefully checking each room was clear, they came across his motionless and bloodied body at the end of the upstairs landing just outside his bedroom.”

The court heard how the tycoon suffered defensive wounds to his hands as well as slash marks to his face.

Two bloodied knives and a trail of blood were discovered at the property and police later discovered messages on Mr Schreiber’s phone that revealed the extent of the resentment he had been harbouring towards the couple.

Mr Feest said: “Built upon a foundation of many years of feeling isolated and unfairly treated by all his family, and fed by being forced to live at Moorhill due to the pandemic and the many injustices he felt had been perpetrated against him, these feelings had led the defendant to repeatedly consider revenge and violence against his ‘toxic’ and ‘gold digging’ mother and Sir Richard, a man he told a friend he couldn’t stand and didn’t have a good word to say about.”

Mr Schreiber has admitted manslaughter over the multi-millionaire’s death, but denies murder. He has pleaded not guilty to attempting to murder his mother. He has also pleaded guilty to dangerous driving on the night of the killing.

The trial continues.