Back in 1961, the TV series The Avengers focussed on the stories of Dr David Keel (Ian Hendry) and John Steed (the recently deceased Patrick Macnee) was only the assistant. After one series, Hendry left and John Steed took centre stage, along came a string of female assistants and as the 1960s progressed the show took on more science fiction and fantasy elements.

Series one to three suffered from having all videotapes wiped, and only two complete episodes of the first series are known to survive. Step in Big Finish who are now half way through adapting the original scripts (where available) and bringing the first series of The Avengers back to life.

This is the fourth boxset of four episodes to be released and has Julian Wadham as Steed with Anthony Howell as Dr David Keel. Three of the stories were adapted by John Dorney (who did the first three volumes), the other by Justin Richards.

The first story, Kill the King was written for TV by James Mitchell, and gives the remarkable contemporary feeling tale of assassins trying to kill the king of an unnamed Far Eastern country visiting the UK to sign an oil treaty. There is plenty of betrayal and intrigue and this is almost entirely a John Steed story with a little bit of Dr Keel grafted in. It is tempting to regard this as the shape of things to come, but that is almost certainly a step to far.

The second story, A Change of Bait (written for TV by Lewis Davison), redresses the balance a bit with the device of one of Dr Keel’s patients falling foul of a gang of insurance fraudsters. There is plenty of action in the London docks mixed with an antique dealers and Keel and Steed bring the villains to justice. Of the four stories this is the most entertaining and of its time.

The third story, Hunt the Man Down by Richard Harris is of a prisoner (Frank Preston), released from jail, who is hunted by friends and police as he tries to retrieve the money he stashed away from the crime that got him jailed. Steed, Keel and Keel’s secretary Carol (Lucy Briggs-Owen) all need to be on their toes as their lives cross Frank’s. There are some wonderful, larger than life performances, and Tim Treloar’s Frank Preston is excellent.

The action moves to more of a science-fiction tale with the final story, Dead of Winter and a frozen Neo-Nazi is discovered at the docks. Cue a return to the dockside, made scientists, fascist organisations and Dr Keel working undercover. There is a deeper apocalyptic plan about a Nazi resurgent and it is all staple 1960s entertainment.

The Lost Episodes ooze style with lot of period touches (I like the old telephones) and plenty of jazz bridges between scenes. These are a great listen and never fail to entertain.

These Lost Episodes continue to impress, and even with half the series to come, fans will already be hoping Big Finish gets the license to either write new stories or adapt the latter lost series (though these would be without Dr Keel).

Extras: Over eleven minutes of behind the scenes interviews on the making of this volume.

Released on 30 June 2015 by Big Finish Productions Ltd.

> Follow Tony Jones on Twitter.

What did you think of the collection? Let us know below…