Theresa May has been accused of acting out of “revenge” after she condemned the National Trust and Cadbury for dropping the word “Easter” from this year’s Easter Egg Hunt.

May described the move as “absolutely ridiculous”, and an affront to a “very important festival” for Christians worldwide. But neither Cadbury nor the National Trust have dropped the word “Easter” from the Easter Egg Hunt.

Cadbury’s website promoting the occasion features the word Easter 14 times and their press release announcing this year’s quest for chocolate features the E-word seven times. They even have a website promoting it with the word “Easter” in the address. As for the National Trust, their announcement of the hunt features the word Easter a further seven times.

May’s rushed statement is in contrast to her usual methodical approach, which is to marshal the facts and then deliver a statement. May took more than 24 hours to comment on Donald Trump’s Muslim ban, and denied journalists a response three times at her press conference. But she commented in a little over an hour on the Cadbury affair.

Civil servants and former special advisers believe that May’s swift response is due to her longstanding antipathy to Helen Ghosh, the National Trust's director-general, with whom she clashed when Ghosh was permanent secretary at the Home Office and May was Home Secretary. (Ghosh left the Home Office in 2012 to take up her current role running the National Trust.)

Civil servants also believe that another Helen, Helen Bower-Easton - who was Downing Street’s official spokesperson under David Cameron and May - was ostracised by May's team due to her perceived closeness to Cameron. (Bower-Easton has since left to head up communications at the Foreign and Commonwealth Office.)

One well-placed source complained that Cameron-era permanent officials had “the mark of Cain” on them in the eyes of the new administration. Another former special adviser said that May was “obsessed with revenge”. A senior figure described the new Downing Street set-up as “thin-skinned”. “The fact is she hates Helen, which is why this has happened,” another Whitehall insider claims.

Downing Street has been asked to comment.