Pillboxes were not the only type of fortifications built at Mellieha in the years before the outbreak of the Second World War. There were other minor military structures but the most important fortification to be built in Mellieha, and the last fort to be built in Malta by the British, was Fort Campbell.
The works on fort Campbell started by the end of 1937 on order of Governor Bonham-Carter to protect the approaches of Mellieha and St. Pauls Bay.
The fort was designed to mount two 6-inch guns. Bonham-Carter insisted that the work on this fort had to be hurried up, because after the Munich Crises of September 1938 it was seen that a war was unavoidable, and all the fortifications being built had to be finished as quickly as possible. It is important to note that the design of this fort reflected the need to contend with a new threat in the form of aerial bombardment. So protection against air attack had become a vital consideration.
The main characteristic of the British fortifications of the late 19th century was the thick ramparts and ditches. But by this time these characteristics were abandoned in favour of thin walls. Therefore, Fort Campbell was built with a thin wall to resemble the field walls of the surrounding countryside, while the plan was broken up by an irregular trace designed to imitate the pattern of the adjoining terraced fields. Perimeter defense was provided by a number of machine-gun posts placed at irregular intervals and in other places there were few rifle loopholes.

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