A man has admitted sending hundreds of racist letters nationwide including calls for a "Punish a Muslim Day".
David Parnham, 35, sent the letters to mosques, Muslim parliamentarians including Lord Ahmed of Wimbledon, the Queen, David Cameron and Theresa May.
He pleaded guilty at the Old Bailey to 15 offences, including soliciting to murder and staging a bomb hoax.
Parnham, of St Andrews Close, Lincoln, was remanded in custody and will be sentenced at a later date.
During his two-year campaign, Parnham sent wave after wave of letters across the country that included white supremacist imagery and threats to minorities, mostly Muslims.
His first letters sent in June 2016 contained a white powder as a hoax poison.
In one letter sent 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 poison hoaxes was so sophisticated that it triggered a chemical attack alert at a Royal Mail sorting office in Sheffield.
The following February, he targeted mosques around the UK. One letter to worshippers in Hull included a warning that they were going to be "slaughtered very soon".
'Awards' for attacks
In March 2017 he escalated his campaign, encouraging recipients of his post at the University of Sheffield to attack ethnic minorities, proposing that he would donate £100 to charity for each killing.
The court heard these letters amounted to soliciting to murder and Parnham's guilty plea to this charge means he could now receive a life sentence.
A year later, Parnham sent out letters headlined "Punish a Muslim Day", offering "awards" for attacks on people, mosques and Mecca.
He was eventually caught after his DNA and fingerprints were recovered from some of the letters, including one that he sent to Dylann Roof, a US white supremacist who is on death row for a mass murder of black churchgoers three years ago.