<p><b>Background and aims:</b> Longstanding uncertainty surrounds the selection of surgical protocols for the closure of unilateral cleft lip and palate, and randomised trials have only rarely been performed. This paper is an introduction to three randomised trials of primary surgery for children born with complete unilateral cleft lip and palate (UCLP). It presents the protocol developed for the trials in CONSORT format, and describes the management structure that was developed to achieve the long-term engagement and commitment required to complete the project.</p> <p><b>Method:</b> Ten established national or regional cleft centres participated. Lip and soft palate closure at 3–4 months, and hard palate closure at 12 months served as a co...