A carer who claimed she suffocated her father because of his "intolerable" multiple sclerosis has been found guilty of murder.
Claire Darbyshire, 36, killed her 67-year-old father Brian at their home in Wykeham Green, Dagenham, east London, on September 2 last year.
The next evening, she was found wandering around cliff tops in Kent, shivering and wet, and asking for help, the Old Bailey heard.
After deliberating for 11 hours and 32 minutes, a jury unanimously found Darbyshire guilty of murder.
Prosecutor Jonathan Rees QC told jurors that Darbyshire accepted killing the former Ford motor company stock controller but claimed it was part of a "suicide pact".
He told jurors: "In essence, she asserts that they had come to this agreement because his life had become intolerable due to multiple sclerosis and she would have nothing to live for once her father had gone."
However, he told jurors that Mr Darbyshire had never expressed any suicidal thoughts before or complained about being in pain to nurses who visited him.
The widower had developed MS in 1995 and over the years his condition worsened so he became bedridden. In 2014, Darbyshire took over as his sole carer.
Medical records revealed he had episodes of "bad temper and aggression" but had never tried to kill himself, Mr Rees said.
The defendant was born Christopher but changed her name to Claire by deed poll in 2008 and has lived as a woman for many years, Mr Rees said.
She and her father led a reclusive life but she befriended the owner of a jewellery shop in Dagenham where she did volunteer work.
The court heard that her friend had noticed over time that Darbyshire was getting "more and more stressed" and complained about having to look after her father.
After the killing, Darbyshire caught a train to the Dover area, having texted the district nurse to visit "asap".
On the evening of September 3, Darbyshire approached a National Trust worker for help and ended up with support services in Canterbury.
Five days later, she mentioned the suicide pact for the first time, saying they had both taken an overdose which failed to work on September 1, before she suffocated her father.
On the morning of Friday September 10 - eight days after the killing - police were called to the Darbyshire home after a neighbour raised the alarm.
Police discovered Mr Darbyshire's body in his bed with a suit, teddy bear and various handwritten notes nearby.
The defendant wrote: "Dad couldn't go on any more being bedbound. He asked me to help him end it. Now I have to end it too as my action is claimed as a crime.
"If it was an animal then you would stop its suffering, but when it comes to a member of your own species you want to prolong the suffering as long as possible.
"We have the cheek to call ourselves civilised. Don't waste your time looking for me. My phone call to the district nurse was my last action."
In another note, she described her father as a "good", "selfless" and "wonderful" man, adding: "He did not deserve to get ill. He was such a great dad."
Following her arrest, Darbyshire told police that she had planned to hand herself in the next day and a signed account was found among her belongings.
In a prepared statement to police, she said her father had "got to the stage where he couldn't stand the misery of his life and the indignity of it any more".
Her defence lawyer, Paul Keleher QC, argued that her actions amounted to assisting a suicide rather than committing an unlawful killing.
Darbyshire, who is pre-operative transgender, was forced to spend five months on remand in a men's prison awaiting trial. During earlier hearings, she had appeared visibly shaken and upset at HMP Belmarsh.
In finding Darbyshire guilty of murder, the jury rejected the lesser offences of manslaughter or assisting a suicide.
The defendant made no reaction as the verdict was delivered, while family members left court in tears.
The Recorder of London, Nicholas Hilliard QC, adjourned sentencing to a date to be fixed and asked for a prison report, saying he wanted to understand the impact of custody "in the particular circumstances".