Reid (Matthew Macfadyen) has dusted off his bowler hat to continue the investigation into the murder of a rabbi, which Inspector Drake (Jerome Flynn) regards as cut-and-dried.

Is Reid persisting as a favour to Deborah, to prove prime suspect Mr Bloom is innocent or because he’s already bored of his sedate life in Bournemouth?

One person not overjoyed to see his former boss in Whitechapel is Jackson (Adam Rothenberg), but it seems the sea air has given Reid a sense of humour as he breezily tells him to call a policeman if he objects to his presence.

Jackson can be excused for being a bit dour, though, as Long Susan is about to be hanged. Can he pull off an audacious escape plan right under Reid’s nose?