On 31 July 1854 the leases of the Howdon works were assigned to the Cookson/Cuthbert partnership, which had within a few years become a potentially formidable competitor to the existing firms of Tyneside lead manufacturers. It seems clear that the partnership had soon been established on a profitable basis and that the extension of supply of lead products had been accommodated by rising demand rather than falling profit margins. In the part of the nineteenth century there is no evidence that the firm had any manufacturing premises and it seems to have been satisfied with selling the lead products of John Locke, Robert Blackett, a firm with which it had an interlocking partnership. Initially, in the early-nineteenth century with lead chemicals available from the Newcastle firm, the decision not to manufacture in London is understandable. As the strength of the Newcastle link declined, it becomes more surprising that growing London competition made such a move unattractive.