IT is perhaps ironic that the first classic Who DVD release of this year is a box-set of stories featuring UNIT – seeing as we sadly lost two stalwarts of UNIT last year in Sarah Jane Smith (Elisabeth Sladen) and Brigadier Lethbridge-Stewart (Nicholas Courtney).

This three-disc set features two stories based on Earth in the near future and both of them have a different Doctor.

Invasion Of The Dinosaurs stars Jon Pertwee as the Third Doctor.

After arriving in a seemingly deserted London, the Doctor and Sarah Jane are arrested as looters and taken to UNIT Headquarters. Once there and reunited with the Brigadier, Sergeant Benton (John Levene) and Captain Yates (Richard Franklin), they get to grips with the real problem – dinosaurs in London.

Discovering a plot to alter time itself, the Doctor has to try and foil the plan – and he isn’t helped by the fact that one of UNIT’s finest is a traitor.

This story sees the first appearance of the Third Doctor’s second car – a futuristic model which came to be known as the Whomobile.

Also, because of the BBC’s short-sighted policy of wiping programmes, episode one of the six is in black and white.

Extras include an appearance of The Doctor and the Whomobile at Billy Smart’s Circus and a look back at the locations used, both then and now.

The second story has Tom Baker as the Fourth Doctor.

The TARDIS materialises in what looks like a quiet village called Devesham; the Doctor, Sarah Jane and Harry Sullivan (Ian Marter) notice that the inhabitants are less than friendly and the village is being patrolled by what look like spacemen.

UNIT is called in, but some of them appear to be different.

It is soon discovered that this is all part of an invasion attempt of Earth by the Kralls and the Doctor has to duplicate himself in order to try and stop the destruction of Earth’s population.

This 1975 story was written by Terry Nation and is a rare non-Dalek Who story by him.

Also unusual is the fact that even though it’s a UNIT story, only Sergeant Benton of the usual team makes an appearance.

In fact, change was in the air as not only was this the final appearance by Harry Sullivan, and Sarah Jane herself would soon be departing; this was the last UNIT story for 14 years (the organisation would next appear in the 1989 story Battlefield with the Seventh Doctor). Although the Brigadier turns up in the 1983 story Mawdryn Undead with the Fifth Doctor.

The extras for this story include interviews with the real-life villagers and a look back at the post-Who career of producer Philip Hinchcliffe.

This is a fitting tribute to both Lis Sladen and Nick Courtney, who are true legends in the history of the show. It’s just a pity that mention isn’t made of their contribution – hopefully they’re saving it for a future release.

Catalogue Number: BBCDVD3376.

Release Date: 9th January 2012.