The first victim of theft immediately rings 999 asking for the police. It was still uncommon for people to have their own telephones at this time, unless you were moderately wealthy and it was not until the late 50s, early 60s, that 'ordinary' folk began to get a telephone. With a huge distribution of public telephones many didn't feel the need to have their own 'phone' for sometime after this date, especially as they had to pay line rental as well as for calls.
The 999 Emergency number was the first of its kind, introduced in the U.K. in 1937.
Made 5 years after the excellent film The Blue Lamp, where Dixon's character was created (although murdered halfway through the film), Dixon is introduced not with the iconic theme latterly known as "An Ordinary Copper" by Jeff Darnell but the whistled tune of "Maybe it's Because I'm a Londoner". Also George Dixon didn't open with the words "Evening All" or end with saying "Goodnight All" which became synonymous with the programme.