"Clangers" are two different things.
One is a 70's
BBC children show where a family of Clangers lived on small moon with the soup dragon, the iron
chicken and the froglets et al. When they spoke, they sounded like someone playing a swanee whistle. They ate
blue string pudding.
The second definition is that one has made a mistake and "dropped a clanger". This is Cockney, not Mockney by the way.
Example one:
Auntie Clanger: WoOowowowoOwOOOowoOOwooo wooo OOoo?
Baby Clanger: OoO.
Other Clangers: OOOOoooo.
Example two:
Bloke 1: Shit.
Bloke
2: What?
Bloke 1: Forgot the whife's birthday.
Bloke
2: Dropped a right
fucking clanger there, mate.