The Mk11 was a development of the Mk10 it entered service in 1985 and took over the Primary 1 crash truck role from the Mk9. Some 24 were built in two versions, sixteen Mk11s and eight Mk11As. The Mk11A had an electro- hydraulic operated high access ladder and cage assembly fitted with a BCF applicator to enable crews to reach the tail-mounted engine of the Lockheed Tri-Star aircraft. Some of these appliances were fitted with new cabs later in their lives.

It could also be used in a domestic fire-fighting role and apart from the normal fire-fighting small gear it carried BA sets, hydraulic rescue kit, a 500watt generator and a 100kg tank of BCF.

The vehicle on display saw service at R.A.F. Lossiemouth, R.A.F. Lyneham

Leading Particulars
Chassis: Scammell Nubian Major 6 x 6
Engine: Rear Mounted Cummins V8 UTA903 Turbo Charged Diesel 500BHP
Gearbox: Allison HT 750, 5 speed automatic transmission
Water Tank Capacity: 5700 litres (1250 galls)
Foam Tank Capacity: 700 litres (150 galls)
Monitor Output: at 14bars-2275 litres/min (500GPM) finished foam at 8/1 expansion 22750 Litres /min (5000 GPM)
Overall length (including monitor) 10.56m
Overall width 2.5m
Overall height (top of monitor unladen) 3.28m
The Mk 11 also had the capacity to produce on the move giving full output from the monitor at 5mph