“Hannah and Cosmo’s engagement dinner was being held at his parents’ house in Kensington.”

This pastiche of a Victorian potboiler would make an excellent film. Hello, Hollywood! Camden calling – murder, real life crime, coming of age, a mystery to unravel, courtroom melodrama, even lunatic asylums. There are some clever sub plots tucked in like the copies of the Girls Own Paper that both Hannah and the titular Mrs Pearcey keep under their beds to read discreetly at night.

The setting is forensically Camden Town 1883. A mother and baby have been slain. Salacious sleuths are on the case. Servants are despatched to bring back the latest news from the new edition of Daily Star.

The twin stories of Hannah and Mrs P wrap around each other like a ball of wool.  From elegant drawing rooms to the backstreets, everyone is on the cusp – the new life that Hannah and Cosmo are planning,  the future father in law admonished for taking illicit photographs, the louche brother who wants to be a theatre producer, the disreputable lover, the confidante moll Dolly, the introverted mother who runs a refuge for fallen women…

Each chapter opens with some sage advices from the Girls Own Paper telling readers to “cultivate a smile”. Or “the power of a literary man is doubled when he gets a cleared headed, sensible wife…” Hannah takes heed as she sews her trousseau…to add extra zest her intended Cosmo is a wannabe reporter on the prime purveyor of scandal, the Star itself. There is some clever wit afoot here…not least in the irony of a parting shot from the Girls Own Paper that “trashy novels and tales do great mischief”. Quite. There is quite a lot of unspooling to do for the finale.