After less than six months production was suspended for the duration of World War II then restarted with the engine moved forward, more interior space and other minor modifications.

It had Singer's overhead camshaft, 1074 cc inline-four engine used in the Bantam range but tuned slightly to give 36 hp (27 kW) at 5000 rpm by fitting a high efficiency "hot-spot" manifold and downdraught SU carburettor, as well as having slightly higher compression.

A chromed front bumper was now standard as were twin aero screens for use when the windscreen was folded flat to reduce frontal area.

Advertising copy incorporated "from the inspiration of the Le Mans model" though the Singer sports-racing link remained deliberately muted after the death of 8 spectators in September 1936's RAC Tourist Trophy on Ireland's Ards Circuit, the Ulster TT.

[8] Nearly all post war production was exported the car being popular with the Elite in India and featured in the collections of a few Maharaja's.

[9] The driving position was also improved, with easier entry and egress, and the Nine Roadster's awkward gearchange was ameliorated as the gearbox was moved back.

While superficially similar, this has an independent front suspension by coil springs and a hybrid, "hydro-mechanical" brake system by Girling.

[10] The steering box also received alterations, mainly aimed at centering it in the chassis so as to simplify manufacturing alternately right-hand or left-hand driven examples.

[16] It used the 48 hp (36 kW), 1497 cc engine from the SM1500 saloon fitted to a virtually unchanged chassis and body, retaining the hydraulic/mechanical hybrid braking system.

[18] Although early 4AD production was still all for export, with the smaller 4AB being regularly available in the United Kingdom, from 1953 1.5 litre cars became available on the domestic market as well.