The Duchess of Sussex was left “deeply shocked and upset” by the publication of parts of a letter she wrote to her father, suffering “considerable distress, damage, humiliation and embarrassment”, according to court papers.

The Duchess’s legal team, which is suing the Mail on Sunday, allege the newspaper "omitted or suppressed" parts of the handwritten letter which demonstrate the Duchess’s “kindness and concern about the UK tabloid media exploiting her father”.

According to papers filed by legal firm Schillings, the Duchess’s claim will see them argue she saw her “deepest and most private thoughts and feelings about her relationship with her father” published “to the world at large... without any warning”.

Her representatives further argue the story, which included an assessment of the Duchess as “showman and a narcissist” by a “so-called handwriting expert”, was part of an “obvious agenda of publishing intrusive or negative stories...intended to portray her in a false and damaging light”.

The newspaper said it would be defending the claim “vigorously”, categorically denying the letter was edited in “any way that changed its meaning”.