of Derby and by the 16th century had become a substantial fortress, reputedly the largest castle in the north of England. During the Civil War, Lathom House was the last Royalist stronghold in Lancashire and as such was of great symbolic importance. In 1644, whilst the Earl was in the Isle of Man, the Countess of Derby successfully defended the castle for three years against a siege. This action is well documented by the historians.

The following year, Cromwell's forces again attacked Lathom House and this time were successful. They so destroyed it that no trace remained. The subsequent edifice of 1720 fell into a ruinous state and it is the west wing of this structure which is presently being restored.

The Archeological Unit of Lancaster University created much interest when the moat of the mediaeval castle was revealed during trial excavations. As work proceeds on the repair of the 18th century building, more fragments of the castle are being unearthed.

The site, one mile from Westhead, near Ormskirk, is close to Lathom Park Chapel and Pilkington's Research Laboratories.