B is for... Benton

Brigadier Lethbridge-Stewart's stalwart right-hand man at UNIT.
Fiercely loyal, brave and dependable, he joined the organisation in its formative stages. He was with them, as a Corporal, when they began investigating International Electromatics, the computer technology firm owned by millionaire Tobias Vaughn. Benton was given a plain clothes assignment to follow the Doctor and Jamie, and to bring them to UNIT's temporary mobile HQ. Later, the Doctor's companions talked him into taking them into London as they wanted to photograph the Cybermen that were hidden in the city's sewer network.

After the Cyberman invasion had begun, Benton manned the radio which allowed the Brigadier to liaise with the missile base at Henlow Down. They destroyed the invasion fleet.
Benton was next seen at UNIT HQ during the incident at UK Space Control, when General Carrington attempted to provoke an interplanetary war. He was now a Sergeant.
He then joined the Brigadier at the drilling project nicknamed the "Inferno Project". On the parallel Earth, the Doctor encountered his alter-ego - the boorish, sadistic Platoon Under-Leader Benton, who was transformed into a savage Primord creature.

Tasked with following the Chinese Red Army delegate Captain Chin-Lee during an international peace conference, Benton was overpowered by an hypnotic force - the work of the Master and his alien mind parasite. The Brigadier wasn't impressed, and Benton hated letting his colleagues down. He took part in the convoy to transport the banned Thunderbolt nerve gas missile, and was wounded in the ambush when it was stolen. Despite his injury, he was keen to remain on duty and to help locate the missing Captain Yates. The Brigadier admired his determination to make up for his earlier failure. He was soon given temporary governorship of Stangmoor Prison, after UNIT had retaken it from a convict revolt.
When the Doctor and Jo got into difficulty in the village of Devil's End, Benton joined Mike Yates in travelling to find them - taking the Brigadier's helicopter. Benton rescued the local white witch, Miss Hawthorne, for which she was eternally grateful. She seemed to become quite enamoured of him, which he found rather uncomfortable. He proved himself an excellent pistol marksman, but prone to be susceptible to airborne cloaks. When the Doctor used Bessie's remote control to capture the Master, it was Benton who took him into custody. He missed out on the pub though, as Miss Hawthorne dragged him into a fertility dance around the village maypole.

After an encounter with the Daleks and their Ogron servants, in which Jo tried to feed him but was stopped by mean Captain Yates, Benton met up with the Master once again. He was due to take some leave, but he was dragged off to the Newton Institute when the Brigadier was called upon to act as an observer to Professor Thascales' temporal experiments. Benton grasped the concept behind the TOMTIT device fairly quickly. Tasked with guarding the device, the Master tried to trick Benton into leaving it when he impersonated the Brigadier over the phone. Benton saw through the deception immediately, when the Master referred to him as "my dear fellow" - something his commanding officer would never do. He made it look as if he had fallen for the trick, but then climbed in through a window to capture the Master when he arrived. Unfortunately, the Master trumped his "oldest trick in the book" ploy with an even older trick - the classic "pretending someone has just come into the room behind you" one.
Later, when trapped with the TOMTIT device, along with Ruth Ingram and Stuart Hyde, the machine caused Benton to regress to babyhood. On being returned to normal after the device had been disabled, Benton found himself naked but for a nappy in front of his colleagues.

When the Time Lord Omega attempted to abduct the Doctor, Benton found himself meeting the Second incarnation of his friend again. Once more, he proved more open-minded than his superior when he accepted that he, the Doctor and the Brigadier had been transported through a Black Hole to another universe. He also took the TARDIS interior in his stride - saying that nothing the Doctor did could ever surprise him. Throwing litter at alien entities was not his finest moment, it has to be said.
Some time later, London began to be plagued by appearances of prehistoric creatures. Benton suddenly found himself facing treachery in his own team, when it became clear that Yates was working for the enemy. His loyalty to the Doctor was absolute, and despite the possibility of court martial he permitted the Doctor to escape - allowing him to knock him out with his Venusian martial arts. Such was the faith the Brigadier had in his sergeant, he had Benton put himself under arrest. He rather enjoyed punching General Finch - but the Brigadier advised him against getting used to hitting superior officers.
Away from the action, Benton was renowned for the quality of his coffee. When the Doctor had to replicate the experiment that had killed Prof. Clegg, Benton volunteered to do it in his stead, as he was dispensable and the Doctor wasn't. This wasn't the only time Benton was prepared to offer up his own life for his colleagues.
With Yates retired from UNIT, Benton found himself promoted to Warrant Officer. Used to having his men follow his orders, he was exasperated by Sarah Jane Smith, as she was not a member of UNIT. The resolution to the problem of the giant K1 Robot was provided by Benton, as he recalled what Prof. Kettlewell had said about the living metal and his anti-pollution metal virus.
In the village of Tulloch, near Loch Ness, the Brigadier used Benton's friendliness with the hotel landlord to smooth their search for the bugging device they suspected was hidden on the premises.

Our last sighting of Benton - now Regimental Sergeant Major - was at the Space Defence Station at Devesham. He was based there with Surgeon Lt. Harry Sullivan when astronaut Guy Crayford re-established contact and prepared to return to Earth after going missing in deep space. He mentioned going ballroom dancing with his younger sister - the only reference to his family. Benton was knocked out, and substituted with a lethal android replica.
When the Fifth Doctor met up with the now-retired Brigadier at Brendon School in 1977, he was informed that Benton had also left UNIT, and was now a used car salesman.

Played by John Levene, Darren Plant (baby Benton). Appearances: The Invasion (1968), then regularly in UNIT stories from The Ambassadors of Death (1970) to The Android Invasion (1975).

• We last see Benton lying on the ground at the Devesham space centre - dead for all we know. A very poor conclusion for such a well-loved character. All the more surprising when you consider that The Android Invasion was directed by Levene's producer, Barry Letts. Luckily his survival gets a mention in Mawdryn Undead - but his new role as a car salesman just doesn't ring true.
• I almost began this post with the old joke: "Benton - first name 'Sergeant' - ..." His christian name has never appeared on screen, but fan fiction has gone with John.
• If Letts was Levene's producer, then Douglas Camfield was his director. Levene had played one of the Cybermen in The Moonbase, and his next role was as one of the Yeti in The Web of Fear - directed by Camfield. He saw the potential in this very insecure young actor, and so cast him as Corporal Benton in a couple of episodes of The Invasion. Another actor was to have played the soldier manning the radio in the later episodes, but he got the sack for persistent lateness - you can guess who by noting who suddenly disappears - and Levene got a call back.
• Camfield intended to use Benton in his next story to be directed - Inferno - so Letts had him brought back for a few episodes of the preceding story in order to better establish him as the Brigadier's No.2.
• The way Ambassadors of Death is edited, it looks like Benton might be the person who poisons poor Dr Lennox in the UNIT cells.
• Levene reprised the role of Benton in the first ever unofficial video spin-off - BBV's "War Time". Michael Wisher played his father. It has recently been re-released on DVD as "War Time Chronicles" with other Pertwee era BBV material. He has also made a couple of Big Finish audios.
• Levene was based in the USA for a number of years but has now returned to his native Salisbury, Wiltshire. Check out the DVD extra by Toby Hadoke on the special edition of Claws of Axos, as well as Levene's video tours of his home town on his website (available on You Tube as well). He's a lovely guy, and gives Tom Baker a good run for his money in the English Eccentrics stakes. Chris Chibnall is a known fan of the Pertwee era - so here's looking forward to the return of Benton.