Why did Sorcha Cusack leave Father Brown as Mrs McCarthy?

ok.co.uk:

Father Brown is back on screens for its 11th series but one of the most loved characters, Mrs McCarthy, hasn't featured since season nine.

Bridgette McCarthy (played by Sorcha Cusack) was Father Brown's (Mark Williams) church secretary at St Mary's. OK.co.uk has all you need to know about why the TV star left in the previous season.

Why did Sorcha Cusack leave Father Brown as Mrs McCarthy? Sorcha Cusack, the Irish actress, hasn't returned for season 11, along with Emer Kenny and Jack Deam.Their absence comes after they were also missing from the previous series.

John Burton, who plays Sergeant Goodfellow, explained why there had been changes to the cast on Twitter last year as he wrote: "Occasionally long running shows need to be refreshed due to artists' availability. "So it means we do have some absentees this year, with a few long-term artists moving onto other projects for their own career progression.This is part of an actor's life, and we must go where the work takes us. "Yes, there are some changes - but they are brilliant changes, and I truly believe you will absolutely love the new/returning characters.