The British racist behind a “Punish a Muslim Day” campaign carried out a two-year sustained programme of hatred that left a lasting legacy of fear among minority communities in the United Kingdom, a court heard on Monday. David Parnham, 36, sent letters to mosques, politicians, Queen Elizabeth and prime ministers David Cameron and Theresa May before his capture when police identified him through fingerprints and his DNA. Two batches of Parnham’s letters urged people to attack Muslims on a designated day in April last year – Punish a Muslim Day - and included a scoresheet for acts that ranged from spitting in a Muslim’s face to murder. The threats prompted increased security at mosques but the day passed off without major incident. Some of the hundreds of letters contained white powder that sparked a full chemical and biological response at a mail sorting office. Others promised Muslim worshippers that they would be slaughtered, a London court heard. The scale of the trauma to the British Muslim community was made clear on Monday with parents cancelling travel plans and women removing their headscarves because of fears they would be attacked. There was still a “fearful anticipation” among British Muslims there would be another explosion of Islamophobia, a community worker said in a statement. Qurban Hussain, a member of the UK’s upper house, said in a statement that he had never read anything like the letter he received from Parnham at his home address during the 47 years that he had lived in Britain. “As I read it for the first time, I felt total shock at its contents - as well as fear, not only for myself but for my family, my home and all other Muslims,” he said in a statement read out in court. Parnham’s anti-Muslim campaign began in July 2016 when he sent white powder in at least 18 letters to people and organisations including the Bank of England and to “Paki filth” at mosques. He sent further letters to the Queen and government officials. Some of Parnham’s letters were signed off “Muslim slayer” and in one batch of letters, he offered to pay £100 to charity for each killing of a member of an ethnic minority. He was an avowed fan of Dylann Roof, a violent white supremacist, who was sentenced to death in the United States 2017 for killing nine black churchgoers in South Carolina. In a letter to Roof in prison, Parnham said that he wished he had been with the American for the shootings, which he described as a “cleansing”. The Briton suggested that he got a sexual thrill from the idea of killing. “If they give you the death penalty, I will have to do something… stabbing people to death in a mosque,” Parnham wrote in December 2016. Parnham, from Lincoln, eastern England, continued to send threatening letters throughout 2017 and 2018 when he embarked on his “Punish a Muslim Day” letter-writing campaign. The campaign for the day of action to coincide with Roof’s birthday received public prominence after the letters were shared on social media. Parnham pleaded guilty last year to sending the letters and admitted charges including soliciting to murder and staging a bomb hoax. He faces sentencing on Tuesday after evidence from psychiatrists about his state of mind. A judge is mulling whether he should be sent to prison or a hospital for continuing treatment for a mental condition. The court heard that doctors agreed that he had autism but were divided on the extent of his psychiatric problems. Parnham told medical experts different stories leading to concerns that he was trying to manipulate the system to get an early release from detention. He told one expert that he remembered little of writing the letters – but gave a full account of contents to others. Martin Lock, a psychiatrist, told the court that he would always be marked out as a “strange individual” even after treatment.