Thomas Schreiber was “consumed with hatred” and the desire for revenge after feeling “humiliated” by his “gold-digging” mother and her partner Sir Richard Sutton.

The trial at Winchester Crown Court heard the aspiring artist was driven by anger at his mother, Anne Schreiber, 66, for “abandoning” his father, David Schreiber, to move in with the baronet at his country estate near Gillingham, Dorset.

The 35-year-old believed he was the only member of the family who remained loyal to his father, who died eight years to the day before the fatal attack after spiralling into depression and alcoholism while living in a cottage owned by Sir Richard.

It was this anniversary, and his mother’s accusation that he was “drunk like his father” while he was commemorating the life of his parent with Sir Richard, that helped “trigger” the “horror show” attack that left his mother paralysed and her partner dead, the defendant told the court.

Read more: Hatred of family led to murder of Berkshire millionaire hotelier, jury told

This “explosion of violence” came after years of simmering resentment occasionally breaking out into fights with his sisters, Rose McCarthy and Louisa Schreiber, with Sir Richard intervening twice.

The defendant accused his mother of being a “gold-digging bitch” by leaving his father for Sir Richard and he felt similar outrage towards his sisters.

Sir Richard was listed at number 435 in the Sunday Times Rich List last year, with an estimated family fortune of £301 million – a rise of £83 million on the previous year.

The guide said Sir Richard’s company owns London hotels the Sheraton Grand Park Lane and the Athenaeum, plus three smaller venues.

He had an extensive property and farming portfolio, including the 6,500-acre Benham Estate in west Berkshire and the Stainton Estate in Lincolnshire.

Read more: Man, 34, admits to manslaughter of Berkshire hotelier Sir Richard Sutton

The most serious of three earlier confrontations in the family was in November 2020 when Schreiber became outraged when his mother offered for Louisa to inherit a chandelier that had belonged to their grandmother.

The ensuing fight ended with Sir Richard hitting the defendant with his walking stick with such force that the cane shattered, which Schreiber felt “humiliated” by.

Schreiber had also felt unequally treated to his sisters after Sir Richard refused to buy him the Volvo car he wanted, instead offering him £10,000 to buy a van so that he could carry his painting canvases in it.

Schreiber would later describe how he was humiliated by this incident and, in March 2021, he wrote to a friend: “I’m so sad to report that my mind is consumed with hatred of the very worst kind towards my family.

“They really hurt me, betrayed me and destroyed all trust. Simply put, I contemplate murdering them all morning, day and night. It’s not what I want to think about but it’s the truth. I want them to suffer.”

He also wrote: “It’s hard to explain the deep emotion of family and with what’s happened is betrayal, gold digging deceit and extreme selfishness when it’s your own mother followed by siblings it’s very hard to accept that.”

Giving evidence, the defendant accepted his “hypocrisy” at his attitude to his family’s finances after the trial heard he lived off a £1,000-a-month allowance granted by Sir Richard to each of the three siblings.

He had also given £100,000 to each of them in 2015 to be used to help buy a property.

However, the money became a curse for the defendant, who felt trapped by the handout as he felt he could not move out of the annexe at the Moorhill estate until he had proven himself a “success” worthy of the expectations of Sir Richard and his mother.

Schreiber described himself in court as a “passionate” painter but felt Sir Richard did not approve of “creativity” and expressed his frustration at not establishing a successful career for himself.

He said that since the age of 18 he had been employed in about 35 jobs, some lasting as short as a day.

After achieving 11 GCSEs at The Gryphon School in Sherborne, Dorset, Schreiber went on to study in Denmark – of which he is a dual-national from his mother, who is Danish – before returning to complete a diploma in music technology and sound engineering at the City & Islington College in the summer of 2010.

These recurring failures left Schreiber resentfully living in the “toxic” environment of Moorhill, which only worsened when the Covid-19 lockdown hit 13 months prior to the fatal day.

In January 2021, he wrote to a friend: “Everything is festering under the surface, eating away at me like a cancer, continuous lies, fakery and betrayal is the order of the day here at home. I despise the feeling of hatred and how it takes a hold of me.”

He also wrote four months earlier: “I have a plan which I’m working on. There are many holes in it but it’s a plan nonetheless. Revenge is at its heart, which I’m sure I’ll regret, but it’s about time.”

Schreiber would later tell a psychiatrist that being forced by pandemic restrictions to remain in the “pressure cooker” atmosphere of Moorhill was a key factor that caused him to “snap” and go “absolutely crazy” and attack his mother and Sir Richard.

The defendant told him: “I am 150% certain if there hadn’t been a lockdown, it wouldn’t have happened.”

Schreiber had denied intending to hurt Sir Richard or his mother, saying that he had “lost control” of himself and he “could not physically stop” his actions.