James Norton and Robson Green return as the unlikely 1950s crime fighting duo, Vicar Sidney Chambers and Police Inspector Geordie Keating, in the third series of Grantchester, produced by Kudos. The six-part series is based on The Grantchester Mysteries by James Runcie.Tessa Peake-Jones is back as Sidney's sharp tongued housekeeper Mrs Maguire who keeps the vicar in check; Morven Christie reprises her role as Sidney's forbidden lover Amanda; Al Weaver returns as the timid curate Leonard Finch; Kacey Ainsworth is back as Geordie's long suffering wife Cathy, Lorne MacFadyen puts his police helmet back on to play DC Phil Wilkinson and Seline Hizli returns as the feisty police secretary Margaret. And of course it wouldn't be Grantchester without the return of the gorgeous black Labrador Dickens.