The design compromises made in fitting the large gun onto the Cromwell chassis resulted in a tank with a powerful weapon and reduced armour.

The Rolls-Royce Meteor gave the British a powerful, reliable engine, which was used in the A27M Cruiser Mk VIII Cromwell tank.

[5] The General Staff brought forward specification A29 for a 45 ton, 17 pounder-armed cruiser tank based on needs identified in the African desert campaign.

At roughly the same time the Tiger I entered service with the German army, placing an immediate need for a 17-pounder armed tank in response.

[7] When the second prototype was tested at Lulworth, it was found that although it would be effective at long range against the current best-gunned tank in German service (the Panzer IV "Special" with the long 75 mm (3.0 in) gun), at shorter ranges it would be at a disadvantage due to its slow firing rate and thin armour.

[8][page needed] The Challenger would be the only British cruiser tank to mount a weapon that could tackle heavier German armour until the arrival of the A34 Comet.

Converting Sherman tanks was simpler than producing Challengers, so it was decided in November 1943 to terminate the A30 production run after the two hundred vehicles had been built, allowing BRC&W to concentrate on the Cromwell.

The War Office expected that this larger ammunition, together with its stowage forward, would require two loaders alongside the commander and gunner in the turret.

The additional length allowed larger hatches to be fitted in the hull while still clearing the turret, providing easier access than Cromwell.

In combat, the Challenger fulfilled much the same role as the Sherman Firefly, providing overwatch for the other tanks in the troop, as its 17-pounder could penetrate almost all German AFVs frontally, unlike the 75 mm.

Its reliability was slightly below that of the Cromwell, as a problem was experienced with track throwing, caused by mud building up in the wheels but this was resolved in the field.

Despite a lower design weight than the earlier A29 specification (32½ not 34 tons), the Challenger was heavy and required dockyard equipment to ship, making it impractical to use in amphibious assaults such as the D-day landings.

[9] No provision was made for deep wading, before the design went into production; as a result, the A30 could not be landed in the initial phase of the Allied invasion of Normandy.

Troops used to the low profile of the Crusader and Cromwell found the height a serious problem, although it was still shorter than the comparable Sherman Firefly.

Confidence in the vehicle grew and it became preferred over the Firefly, being lower, faster and more manoeuvrable but the early bad reputation persisted with others.

An additional stowage bin was provided on the glacis plate for a large camo net and return rollers were added to the tracks.

[19] The Avenger suffered in trials as the engine had to remain running to use the turret traverse motor, because the noise and exhaust could give the vehicle away.

[19] While the Avenger was only used for trials and was ultimately unsuccessful in comparison with the purpose built vehicles, it provides an example of what could have been possible for the Challenger had it not been forced to accommodate a second loader in a larger (four-man) turret in its design.