OK...OK..I know Reagan used the famous Ford Consul but Cortina NHK 296M made more than a few appearances - sometimes with different plates..
Oh crikey, don't get me started on the numberplates...! (I only know this stuff because in a former life I co-wrote a book on The Sweeney and, before the internet could check such things, I wasted countless hours trying to keep track of all the cars.) Yes, the plate NHK 296M is often seen on a blue Cortina 'squad car', as well as on a police car earlier in the second season. And later on in the series, a white Sweeney Cortina (DLO 97M) appears, only it used to be blue! (One stunt too many, perhaps.)
As far as I can work out, Cortinas feature prominently in getting on for twenty out of 54 episodes, including a blue Cortina Ghia, a blue Cortina 2.0 XL, a blue police Cortina with lights, a dirty white Cortina complete with red ‘go faster’ stripes, a blue Mk II Cortina, a blue 2.3GL Mk IV Cortina, a silver/grey Mk IV Cortina, and a sunshine-yellow Cortina Mk III that's driven through a handily-placed wooden gate. Perhaps the best bit of concentrated Cortina action is in the episode 'Visiting Fireman', where Regan drives a faded green Cortina II (in reverse) at a burgundy Mk I. (There was a great website just devoted to the cars in The Sweeney, but it seems to have vanished.)
Trying to bring things up to date (slightly), the TV series Life on Mars at one point had the working title Ford Cortina, and of course Gene Hunt (in 1973) is seen driving what's essentially a 1974 Ford Cortina 2000E with a GXL grill and headlights (and apparently a spoiler from 1975). Television, eh?
And, to bring things even more up to date, and remembering this forum, I could definitely see a 2020s Sam Tyler driving a Tesla. Guv.