triumph? I agree. 1957-65 tank badge by this picture. Being police bikes I presume 650s - Tiger 110 or maybe Saint? umm...may be Saint, but not sure...
1964 would be a 6T Thunderbird, the TR6P Trophy Saint wasn't introduced until '67.
I'll go for James Cadet (1957-) http://www.simplywizard.co.uk/folders/level3/l15.htm (*more closer, tank badge is visible ) It's a long time since I've seen this movie, is it the one where a young Baldrick (Tony Robinson) ends up in the drink?
This shade of green indicates a 150cc Cadet M16 from the last 2 years of the factory, '65-66.