“Stop! Or I’ll say stop again!” (British policeman or unarmed officer joke)

“Stop, or I’ll shoot!” is a classic line of what an armed police officer shouts at a suspect. American comedian Robin Williams (1951-2014) said in Robin Williams: An Evening at the Met (1986):
 
“You know in England if you commit a crime, the police don’t have a gun and you don’t have a gun. So if you commit a crime: ‘Stop! Or, or I’ll say stop again!’”
 
The British policeman (or unarmed officer) joke is a classic, although Williams (who used the joke over many years) is not always given credit for it.
 
 
Wikipedia: Robin Williams
Robin McLaurin Williams (July 21, 1951 – August 11, 2014) was an American actor and comedian. Starting as a stand-up comedian in San Francisco and Los Angeles in the mid-1970s, he is credited with leading San Francisco’s comedy renaissance. After rising to fame as Mork in the sitcom Mork & Mindy (1978–82), he went on to establish a career in both stand-up comedy and feature film acting. He was known for his improvisational skills.
 
IMDb (The Internet Movie Database)
Robin Williams: An Evening at the Met (1986 TV Movie)
Quotes
Robin Williams: You know in England if you commit a crime, the police don’t have a gun and you don’t have a gun. So if you commit a crime: “Stop! Or, or I’ll say stop again!”
 
Google News Archive
6 August 2000, The Register-Guard (Eugene, OR), “Guard,” Oregon Life, pg. 3G, col. 1:
“Kind of like (saying), ‘Stop! or I’ll say, Stop! again.’”
     
Google News Archive
25 February 2001, Milwaukee (WI) Journal Sentinel, “Big investment in safety for city housing pays off,” pg. 6B, col. 2:
“And I’d heard all the jokes about un armed officers: ‘Blow your whistle and tell a perp to stop, or I’ll say stop again,’ you know, like European police officers.”
(Donald Werra of the Public Safety Department.—ed.)
 
YouTube
Robin Williams: Cops
Hot Dog Films
Uploaded on Dec 6, 2007
THIS WAS DOWNLOADED FOR AUDIOCOMEDY.NET.
2:10
“In England, the police don’t have a gun and you don’t have a gun. So, if you commit a crime: “Stop! Or I’ll say stop again!”
 
The Telegraph (UK)
‘In England, if you commit a crime, the police don’t have a gun and you don’t have a gun. If you commit a crime, the police will say, “Stop, or I’ll say stop again”’
Robin Williams at The Wimbledon Theatre in 2008 at the comedy We Are Most Amused to mark the 60th birthday of HRH The Prince of Wales.
     
Sky News (UK) 
Sunday 02 March 2014
Russia Stands With Putin Over Ukraine Gamble
Vladimir Putin’s defence of his country’s interests in east Ukraine and Crimea may be unpopular abroad but has home support.
Katie Stallard
Asia Correspondent
(...)   
One commentator characterised US President Barack Obama’s latest statement on Ukraine as: “Stop, or I’ll say stop again.”
 
The Guardian (UK)
Robin Williams’s best-loved gags
From the satirical to the political to the downright weird, here are some of the comedian’s best one-liners
Richard Vine
Tuesday 12 August 2014 14.18 EDT
(...)
“In England, if you commit a crime, the police don’t have a gun and you don’t have a gun. If you commit a crime, the police will say: ‘Stop, or I’ll say stop again.’”
 
Twitter
Donna McRobbie
‏@Domash101
In Eng, if u commit a crime, the police don’t have a gun & u don’t have a gun. So if u commit a crime, stop! Or I’ll say stop again. RW X♥
3:46 PM - 8 Sep 2015