Not long after the Prime Minister's 11am announcement, rumours began to swirl on social media that Perrior would not be joining May on the campaign trail.
Political blog Guido Fawkes reported Perrior as saying: "Always said I wouldn’t stay past an election. Good decision, right choice. A vote for Theresa May and a Conservative Government is the only route forward. As for me – new opportunities ahead. Exciting times!"
PRWeek understands that Perrior updated her Facebook profile earlier today to indicate that she was leaving her job. She will stop working at Downing Street this week.
Political commentators were quick to speculate that Fiona Hill, May’s joint chief of staff, would run the Conservative’s election campaign.
This means more to political journos than voters, but PM chief of staff Fiona Hill to be Comms Director for election now Katie Perrior left— Chris Ship (@chrisshipitv) April 18, 2017
Jo Tanner, with whom Perrior founded the agency iNHouse Communications, said: "Katie always maintained she wouldn't continue in the job post a General Election so her departure comes as no surprise to those of us who know her well."
Tanner and Perrior remain on good terms, although it is not clear whether Perrior will try to return to iNHouse. She had been obliged to give up her shares in the company on taking the Downing Street role, and so has no longer has any formal link to the agency.
Path to Number 10
She had taken an extended leave of absence from her role as co-director of iNHouse Communications in order to work on May’s leadership campaign before she took up the Downing Street job.
Perrior ran Boris Johnson’s PR during his 2008 bid to become London Mayor, as well as his successful 2012 re-election campaign.
Perrior did no fit the mould of prevous directors of comms to the prime minister. She was the first woman to hold the position. She is from a working-class background and, unlike her recent predecessors, was not a former journalist.
Sam Burne James also contributed to this report