Allsop was seriously implicated, though he escaped punishment, in the plot of
Felice Orsini, in which three bombs were thrown at
Napoleon III in Paris on 14 January 1858. The casualties to bystanders included eight deaths and 150 injuries. , 1858, engraving published in the
Illustrated London News, from a photograph of a police exhibit. The bomb was made by Joseph Taylor of Birmingham, with whom Allsop dealt. Orsini was travelling on an old British passport issued by the
Foreign Office to Allsop, at the request of a business, as
Lord Palmerston explained in Parliament. Allsop managed to escape after the event to America; and stayed in
New Mexico for some months, writing home to
George Jacob Holyoake from
Santa Fe.
Simon Francis Bernard stood trial for his own involvement. It came out that the bombs employed in the attack were ordered by Allsop in
Birmingham; but that he gave his name and address. The government offered a reward of £200 for his arrest. Holyoake and
John Baxter Langley then had an interview with the home secretary, and brought an offer from Allsop to give himself up if the reward was paid to them to be applied for the expenses of his defence; the reward was withdrawn. Allsop returned to England, on 17 September. ==Later life and death==