Lambretta DUE50 Owner's Manual page 21

CONTROLS AND GAUGES
Ignition Switch
OFF In this position, power is turned off and the engine stops. The
key may then be removed.
ON In this position, all electrical equipment is powered, and the
engine may be started. The key cannot be removed in this position.
LOCK In this position, the handlebar is locked (see following instructions).
The key may then be removed.