Good shots of volunteer crews patrolling the River Thames on small boats.
Full title reads: "Our 'Mosquito' Navy".
VS Volunteer crews being briefed and trying out the light machine guns on board small motor boats taken over from private pleasure use for defence duties along rivers and inland waterways.
VS. of a flotilla of the small motor boats cruising along river and out into estuary. Cut away to shot of officer looking through binoculars.