Funfair BSA Light Pattern.

This 1930s BSA spotted at Carters Steam Fair near Alexandra Palace in north London.

Pics taken with a mobile so a bit grainy.

The rifle gets a mention on the Carters website too, along with the others on the rack:

http://www.visit.carters-steamfair.co.uk/rides/slugshooter/slugshooter.html

These (rather better) pics are on the Carters website: