One man has admitted that he sent hundreds of racist letters across the country, including calls for "punishing as Muslim Day."
David Parnham, 35, sent the letters to mosques, Muslim MPs including Lord Ahmed of Wimbledon, the Queen, David Cameron and Theresa May.
He pleaded guilty to the Old Bailey for 15 crimes, including asking for murder and bombing a bomb.
Parnham, of St. Andrews Close, Lincoln, was taken into pre-trial detention and will be sentenced at a later date.
During his two-year campaign, Parnham sent wave after series of letters throughout the country, including images of white supremists and threats to minorities, mostly Muslims.
His first letters, sent in June 2016, contain a white powder as a hoax poison.
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In a letter to David Cameron, Parnham wrote: "Allah is great" and in others sent to mosques he wrote "Paki filth".
Three months later, Parnham sent another wave of white powder letters, including those addressed to the Queen and Theresa May respectively.
One of his hoaxing sessions was so advanced that it triggered a chemical attack alarm at a Royal Mail sorting office in Sheffield.
The following February he was targeting mosques in the UK. One letter to the worshipers in Hull contained a warning that they would be "quickly slaughtered".
& # 39; Awards & # 39; for attacks
In March 2017, he escalated his campaign, encouraging recipients of his position at the University of Sheffield to attack ethnic minorities, with the proposal that he would donate £ 100 to a charity for every murder.
The court heard that these letters amounted to begging to kill and Parnham's guilty plea for this indictment meant that he could now get a life sentence.
A year later, Parnham sent letters with the head & # 39; Punishments on a Muslim Day & # 39 ;, with & # 39; awards & # 39; for attacks on people, mosques and Mecca.
He was finally caught after his DNA and fingerprints were recovered from a number of letters, including one that he sent to Dylann Roof, an American white supremacist who was on death row three years ago for a mass murder of black churchgoers.