In British English, the noun panda has been familiarly used to designate a police patrol car having a broad white stripe painted on a dark background. This noun has also been used attributively, as in panda car, panda driver and panda patrol.

This use of panda alludes to the black-and-white fur of the giant panda, a large herbivorous bearlike mammal.

—Cf. also, in British English:
– panda, denoting a type of pedestrian crossing distinguished by black-and-white chevrons marked on the road, and having traffic warning lights activated by people wishing to cross;
– jam butty, denoting a police patrol car having a red stripe painted on a white background.

In the sense of a police patrol car, the noun panda occurs, for example, in Coupes and robbers: Triumph GT6 on patrol, by Barrie Mills, published in the Liverpool Echo (Liverpool, Merseyside, England) of Friday 16^th October 1998:

WHEN the blue lights flash in your rear-view mirror these days, the chances are that the officer pulling you over is behind the wheel of a purposeful-looking Volvo T5 or even a big Jag.
Back in the 60s, villains could have been forgiven for looking twice if this sporty little number was on their tail.
The Triumph GT6 may not be the world’s best-looking police car, but it certainly gave its drivers a bit more fun than the average Panda.

The earliest occurrences that I have found of the noun panda used in the sense of a police patrol car are from two accounts of an experiment in neighbourhood policing which was carried out in Accrington, Lancashire, England—accounts published in British newspapers on Tuesday 13^th September 1966:

1-: The following is from one of those accounts, A policeman in his parish, by Dennis Johnson, was published in The Guardian (Manchester, Lancashire, England):

Four special one-man patrol cars—painted blue with a broad white stripe and known as “Pandas”—are on the road for 24 hours a day, each covering two beat areas.

2-: The following is from the other account, Back to the ‘village bobby’, by Harry Hawkes, Mail Crime Reporter, was published in the Evening Mail and Despatch (Birmingham, Warwickshire, England):

The Accrington experiment is, in fact, a two-in-one scheme—a combination of the “neighbourhood” policing and mobile policing which have been tried separately in various parts of the country.
Eight areas, or beats, have been formed. Each has its own “village bobby” dealing with everyone and everything on it.
Each policeman lives on his own “manor” and arranges his eight hours’ duty according to when he is most needed. He either walks or cycles.
He does not leave his beat and when he is off duty it is not covered by another man.
That does not mean that the beat is unprotected. This is where the mobile policing system is combined.
In addition to the “village bobby” a conspicuous “Panda” car (they were originally black and white) patrols the beats—each car touring two beats.
Again like the beat man on foot, the same cars and drivers are kept on the same beats, so that everyone gets to know them and vice versa.
[…]
The whole basis of the experiment hinges on the personal two-way radio sets carried by all police officers in the area.
In the distinctive two-tone blue Panda cars, with “Police” painted in large letters on each side, it is the driver, not the car, that has the radio.
Panda drivers are encouraged to park their vehicles in places where they can be seen by the public and assist people.
“Carrying his own radio, the driver is on immediate call even though he leaves his vehicle,” said Superintendent Hammond.
“The beat man, too, is on immediate call through his radio wherever he may be.
“His sense of loneliness tends to disappear because he knows he need only use his microphone to talk to his colleagues.
“We have built up a team—a nucleus of officers eager to serve the public.”
With beat policemen on the spot and frequent patrols from the Panda cars, all superimposed on the normal Z-car ¹ and C.I.D. ² operations, together with a town centre patrol of uniformed officers, police presence has a deterrent effect on wrong-doers.
[…]
I went for a demonstration run in a Panda patrol with P.c. George Foster driving. His radio was on. His call-sign was his “collar number” 599.
Control room at Divisional Headquarters had received a 999 ³ call about a car crash and directed vehicles “on the patch.”
We arrived within minutes. Already the local Panda patrol was there, with other police officers alerted through their personal radios. Impressive speed.
In the control room the Station Sergeant can keep in touch with county headquarters and he operates the master set for the personal radio network.
A magnetic board nearby tells him which beat officers, Panda patrols and crime cars are on duty and to call them takes only a second.

¹ The noun Z-car designates a police patrol car, after Z Cars, the title of a popular British television series, from the radio call-sign zulu allotted therein to a group of such cars. This series centred on day-to-day policing in the fictional town of Newtown, in Northern England; produced by the BBC, it ran from January 1962 to September 1978.
² C.I.D. is the abbreviation of Criminal Investigation Department, denoting the detective division of a police force.
³ The noun 999 denotes the telephone number used to contact the emergency services in the United Kingdom.