Met Police Air Support Unit was formally launched on 26 Nov 1980 at Lippitts Hill with a mix of Bo.105 and Bell 222. The Met had used helicopters in a limited capacity - 3x Sioux AH.1 had been loaned from the British Army for trials in Jun 1967 and 2x Enstrom F-28 were operated from 1976 - but Nov 1980 was when a full time service was constituted.
It is fair to say that
The Met was skeptical about the benefits of a proposed National Police Air Service and it was three years before it reluctantly signed up to
NPAS, in Mar 2015.