Simon Brodkin, whose previous pranks include interrupting Kanye West on stage at Glastonbury and giving out golf balls with swastikas on at the reopening of Donald Trump's Turnberry golf resort, was promptly removed by security and pursued by journalists, not before adding “Boris told me to do it,” referring to the current foreign secretary.
A P45 is the reference code of a form titled "Details of employee leaving work" which is given to workers when their employment is terminated.
The prime minister's spokesperson confirmed that Brodkin was later arrested for breach of the peace.
May's speech went from bad to worse as she suffered a coughing fit and had to be given a lozenge on stage. In the speech May apologised to her party for losing seats in June's general election.
The speech concluded with a letter sign falling off the wall as she spoke.