THE second instalment in a year-long 50th anniversary celebration, this story faces two obvious challenges: capturing the atmosphere and style of a Patrick Troughton adventure, and propelling the ongoing story arc forwards towards its inevitable conclusion in November.

It’s almost a prerequisite of any Second Doctor story to adopt the “base under siege” format which his era so popularised, and of course no exploit from this period would be complete without the inclusion of Fraser Hines as Jamie McCrimmon, the 18th century Highlander who appeared in all but one of Troughton’s stories.

Hines’ considerable talents include a near-perfect impression of “his” Doctor, complete with Troughton’s vocal tics and mannerisms, which adds weight to any contemporary audio he appears in. He also does a very good job mimicking Wendy Padbury as girl genius Zoe Heriot, and is assisted by a contribution from Evie Dawnay as scientist Dr Sophie Topolovic.

Shortly after Zoe joins the TARDIS crew, the time travellers are forced into an emergency landing on a scientific research base in the year 2724, a survey mission investigating the effects of a nearby pulsar, which emits powerful forces which can even twist time, leading to fluctuating time zones that affect both the planet and its inhabitants.

Apart from obvious perils including earthquakes and the aggressive survivors of the base, there is also the matter of the extinct indigenous civilisation, which disappeared without trace, and an apparently intelligent shadow form which is picking off the crew one by one…

It’s a suitably atmospheric story which recreates perfectly the claustrophobia and menace of similar tales from the 1960s, thanks largely to a first-rate script from Simon Guerrier and stand-out performances from Hines and Dawnay, and sound design which adds to the growing sense of menace.

Without giving too much away, the ongoing arc is recognised in spectacular fashion, and sets up things nicely for subsequent instalments without damaging existing continuity. Quite how this will resolve itself in the final story is something we will have to wait to discover, but it’s certainly whetting this reviewer’s appetite for future episodes.

Admirably capturing the black and white era of Doctor Who, this is an expertly-crafted, glorious celebration of Patrick Troughton’s tenure as the Time Lord, and exactly the sort of story we want to be enjoying as part of the show’s golden anniversary.