1. Jimmy Perry dreamt up Dad's Amy as a way to get himself a juicy role on TV
As a veteran stage actor, Perry had scored a few small roles on television but intended to play the scene-stealing black market spiv, Private Walker, to get himself a breakthrough part. However, David Croft advised Perry that being both writer and performer might cause issues so James Beck was hired instead.
2. Arthur Lowe was touchy about trousers
When approached for the role of Captain Mainwaring, Arthur Lowe was a little wary of being involved in comedy that was too lowbrow so insisted on a clause in his contract specifying that he would never have to appear on the show without his trousers. When the first episode of Series 6 included a scene where a grenade ends up down Mainwaring's trousers, Lowe refused to go ahead with it, so things were quickly rewritten so that Corporal Jones ended up with the bomb in his britches.
3. There are three episodes of Dad's Army you can never watch
Between 1967 and 1978, the BBC routinely deleted archive programmes to free up storage space and three episodes from Series 2 of Dad's Army suffered this fate and are thought to no longer exist. It used to be worse though - there were originally FIVE episodes from Series 2 that were missing in action until an appeal by the BBC unearthed copies that had been dumped in a skip, discovered by one of the Elstree Studios staff and taken home.
4. Clive Dunn was 22 years younger than Corporal Jones
Clive Dunn played the oldest guardsman, Lance Corporal Jones, but was actually one of the youngest cast members. Being just 48 when he took the role of the 70-year-old, he was the only principal actor not playing a part approximate to their own age. From early on in his career, Dunn's trademark turn was that of a doddering old man and his relative youth meant that he was able to take on a lot of the physical comedy that the older cast members were no longer capable of.
5. Dad's Army was not originally called Dad's Army
Perry and Croft's comedy might well have hit the airwaves under its original name, The Fighting Tigers, had it not been for the intervention of Michael Mills, head of comedy at the BBC. He didn't like the name and thought up 'Dad's Army' himself. Mills also changed a few of the character's names and the location from Brightsea-on-Sea to Walmington-on-Sea.
6. Audiences originally disliked Dad's Army
Before it was broadcast, Dad's Army was shown to test audiences to gauge reaction and the results were not good, with most either being indifferent or actively disliking it. Such a negative report could well have stopped the show going ahead but the production team sneakily sat on it until the first episode had been broadcast. Immediately well received, the show went on to regularly gain audiences of 18 million viewers.
7. Dad's Army actually takes place in flashback
The very first episode of Dad's Army, The Man and the Hour, begins with a scene set in the 'present day' - 1968, when the show was first broadcast. In the scene, an elderly Mainwaring gives a patriotic address recalling his time in the Home Guard as a way to endorse Harold Wilson's "I'm Backing Britain" campaign. So all that follows - over the whole of the 80 episodes of the sitcom - is technically a flashback!
8. Dad's Army had a sequel
There were Dad's Army spin offs including a 1971 film and a 1975 revue-style stage show but there was also a bona fide sequel in the form of a BBC radio sitcom called 'It Sticks Out Half a Mile' which aired after the TV show ended. The pilot episode followed Captain Mainwaring and Sergeant Wilson after the war but, when Arthur Lowe died in 1982, the show was recast to include the characters of Warden Hodges and Private Pike, along with Wilson, and broadcast in 1983.
9. A statue was erected to honour the show
A life-size bronze statue of Arthur Lowe as Captain Mainwaring was unveiled by writer David Croft in 2010. Erected in Thetford, Norfolk - which doubled for Walmington-on-Sea in the exterior shots of the show - the statue features Mainwaring sitting to attention on a bench at the end of a winding pathway decorated with the Union Flag arrow head as featured in the opening credits of Dad's Army.
10. The Dad's Army cast could have been very different
The BBC were not keen on the casting of Arthur Lowe as Captain Mainwaring because of his long-running role on ITV's Coronation Street so Jon Pertwee (the third Doctor Who) and Leonard Rossiter (Rising Damp, Reginald Perrin) were considered for the role instead. In addition, David Jason (Only Fools and Horses) was David Croft's first choice for Lance Corporal Jones and Jimmy Perry wanted Jack Haig, who would later star as Monsieur LeClerc in 'Allo 'Allo! The role of Sergeant Wilson was also originally envisaged for prolific TV actor Robert Dorning who went on to appear in the classic episode "Something Nasty in the Vault" as a bank inspector.