The man accused of driving a van at worshippers leaving Finsbury Park Mosque had originally planned to attack in Mayfair, a court has heard.
Darren Osborne, 48, faces trial for the murder of 51-year-old Makram Ali and attempted murder of nine others who had left Finsbury Park Mosque shortly after midnight on June 19 after offering late-night Ramadan prayers.
A handwritten note found in the back of the van used in the attack complained about terrorists and child groomers roaming the streets while branding Labour leader Jeremy Corbyn a "terrorist sympathiser" and Mayor of London Sadiq Khan "a disgrace".
The letter continues: "This is happening up and down our green and pleasant land. Feral inbred, raping Muslim men, hunting in packs, preying on our children.
"Get back to the desert you raping inbred b******s and climb back onto your camels."
The jury at Woolwich Crown Court heard that Mr Osborne had not previously exhibited any racist ideologies, but turned into a "ticking time-bomb" after watching BBC drama Three Girls, based on the true story of a Rochdale-based grooming gang.
A search of his Internet history also found searches for Britain First, the English Defence League and a video, reported to be fake, of Muslims celebrating the Paris terror attack.
Osborne's partner said he had become "obsessed and brainwashed" and that he was a "loner and functioning alcoholic".
A witnesses report hearing Osborne yelling "I want to kill more Muslims" as he was pinned down after the attack while another witness said he was "constantly smiling" and saying "I've done my job, you can kill me now".
'Original target was Grosvenor Square'
Osborne, of Glyn Rhosin, Cardiff, had rented a van and driven to London on June 17 for the purpose of an attack on the controversial Al-Quds march the following day, the jury heard.
Prosecutor Jonathan Reese QC told the court while opening the trial on Monday (January 22), that Osborne had asked a black cab driver for directions to Grosvenor Square in Mayfair, home to the US embassy and former Prime Minister Tony Blair, where the march had congregated.
Mr Rees said: "We are not able to say quite how close the defendant came to the marchers or Grosvenor Square, although it seems likely the defendant was prevented from carrying out an attack because of the road closures that were put in place."
Perturbed, Osborne is thought to have travelled to Forest Hill in south London and asked a man at 8pm where the nearest mosque was.
He was told there was no mosque in the area and he drove north to Finsbury Park where he was guided to the mosque by another motorist, arriving at 11.30pm.
The family of 51-year-old Makram Ali were in the courtroom when CCTV footage was played showing Mr Ali collapsing on the pavement and a crowd gathering shortly before a white van sharply turns and ploughs into the crowd, mounting the curb.
Mr Ali later died in hospital and several other people suffered injuries as a result of the attack.
The trial at Woolwich Crown Court continues.
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