The shape of the Mark I Medium hull was very distinctive. The back was a simple armoured box; the front plate was high and perfectly vertical. Between them, from the armoured hood of the driver at the right of the vehicle six armour plates fanned out to the left, making for a complex hull geometry at that side. In all the tank made an ungainly squat impression. The crew of five was only poorly protected by 6.25 mm plating, rivetted to the chassis, barely enough to counter the threat posed by light machine guns. With its many shot traps the vehicle was unable to withstand even anti-tank rifle fire and it had a high-profile. The internal lay-out worsened this vulnerability as the petrol tanks were inside the main compartment.