Donald died on 18 November 2008 aged 85. He was born on 12 June 1923 in Gloucester. When he was 2-years-old his family moved to Monmouth where his father was a well-respected dentist. He was educated at Monmouth School until the age of 18 and then went to Cardiff University to read Civil Engineering. After only one year he enlisted in the RAF and from 1942-1946 he was a pilot flying Lancaster Bombers. He always maintained contact with his crew attending regular reunions.

From 1947-1952 Donald was an undergraduate at Guy's where he was in the rugby team. He moved to UCH for his postgraduate studies first as a House Surgeon then as a Registrar (1953-1955) and Senior Registrar (1955-1961). He performed original research in electromyography with Barry Wyke at a time when it was first introduced into England. Under the tutelage of Willi Grossman he developed a lifelong interest in Rapid Maxillary Expansion (RME).

He was appointed to a consultant post at the Royal Preston Hospital in 1961 and covered an immense area involving eight health districts. He served on numerous local and regional committees and played a pivotal role in developing orthodontic services in North Lancashire and South Cumbria. With vision, foresight and skilful negotiation he established the present pattern of consultant cover with four consultants serving his original patch by the time he retired in 1989.

Donald Timms gained an international reputation for his research on RME and became one of the world's leading exponents of this technique having completed well over 1,000 cases. He always said that the first 500 were the most difficult! He gave lectures and courses all over the world. At his retirement dinner the menu card showed him travelling the world on RME.

As well as numerous publications on RME, Donald was best known for his excellent book on the subject. This is essential reading on the subject; it is difficult to write a paper on RME without referring to Timms.

Donald always emphasised the medical aspects of RME in relation to improvements in nasal airway and worked closely with his ENT colleagues. He foresaw the importance of the nasopharyngeal airway in craniofacial development and obstructive sleep apnoea. The profession is indebted to his pioneering work in this field.