Define Twenny Spot Meaning

Twenny Spot
An 8th of Cannabis in England. Costing £20 unless you're from a shit place like Phetford where it's like £25.

Jayce: Alright Ben, you got a cheeky twenny spot in?
Ben: Yeah mate, come down whenever. Only 2 gram though mate.
Jayce: Get fucked then mate.
*Hangs Up*
By Kissee