Morningside speed, n. — Green’s Dictionary of Slang

Morningside speed n.

[the socially select area of Morningside, Edinburgh]

(Scot. drugs) cocaine.

1993		I. Welsh Trainspotting 74: Mitch lines up some Morningside speed, cocaine, on the formica-top table.
1999		I. Rankin Dead Souls 4: ‘Morningside Speed’ is cocaine.