As consistently entertaining as their own spin-off series or occasional adventures with the Sixth Doctor have been, there is nothing like pairing up those intrepid investigators of infernal incidents Jago and Litefoot with the Fourth Doctor. They do spring from the Tom Baker-starring classic serial ‘The Talons of Weng Chiang’, after all. The opener of the sixth series of Fourth Doctor audios from Big Finish reunites the dream team – with Romana II taking the place of Leela – for yet another murky mystery in Victorian London.

This time, the TARDIS is in the duo’s neck of the woods to investigate a bizarre and unstoppable crime spree that is covering the capital – a burglar by the name of The Knave is breaking in and out of seemingly unimpeachable places. This should be a doddle for our four heroes to solve – but what happens when one of them turns out to be the enemy?

Justin Richards has written for Jago and Litefoot and in this period on many an occasion, so he naturally weaves one of his reliably good yarns here. A good balance is struck between the two sets of characters, meaning it never feels like a Jago & Litefoot story hidden under a Doctor Who logo. It has to be said that the reveal of the true identity of The Knave is an obvious one, but Richards seems to know this as he dispenses with the twist in the early minutes of part two.

There is some great character work in this two-parter, as well. The highly capable Romana bounces well off the gentlemanly George Litefoot – the way she immediately assumes he wants her opinion on the case instead of the Doctor’s is priceless. Likewise, it is a lot of fun to hear Christopher Benjamin get to let loose with a bout of growling and howling when – spoilers incoming – Jago turns into a were-monster. Tom Baker, meanwhile, clearly relishes larking about with his old co-stars and is on fine, fruity form.

K-9 – that modern mechanical marvel of canny canine charisma, as Jago colourfully calls him – is the real star of the show, however. A lot of humour is mined from his acting as the Emcee at the New Regency Theatre in Jago’s absence and from the Doctor’s indignance at his dog being smarter than he is. K-9 even cracks wise, in a Christmas cracker joke sort of a way, as he gets a rib-tickling line about eating cakes with “electric currents” in.

In the episode commentary at the end of the release, the crew talk about this season being set in Season 18, at the start of John Nathan-Turner’s reign. While this release draws too much from the ethos of earlier seasons to feel part of that era (including some delightfully Dudley Simpson-esque music from Jamie Robertson), it is well worth a listen for the classic Victorian mystery and the nostalgic thrill of hearing these old friends reunite one more time.

DOCTOR WHO: THE BEAST OF KRAVENOS /  PUBLISHER: BIG FINISH / DIRECTOR: NICHOLAS BRIGGS / WRITER: JUSTIN RICHARDS / STARRING: TOM BAKER, LALLA WARD, JOHN LEESON, CHRISTOPHER BENJAMIN / RELEASE DATE: OUT NOW