However, his most important contribution to Hong Kong was made as the first commissioner of ICAC, which was formally established in February 1974 amid the outcry over Peter Godber, the corrupt police chief superintendent who fled to England rather than answer questions about personal assets worth $4.3million.

More than 30 years after it was established, ICAC has made an enduring contribution to Hong Kong's transformation. A city notorious for ambulance drivers and firefighters demanding 'tea money' before picking up patients or turning on their hoses has become one of Asia's financial powerhouses, with a reputation for clean and efficient government.

Outrage over such corruption reached its peak in demonstrations against Godber and, facing growing public outrage over police corruption, the then colonial governor, Sir Murray MacLehose, decided that Cater was the man for the job.

Cater rose to prominence in 1967 when, as deputy colonial secretary and special assistant to the then governor, Sir David Trench, he headed a secret committee that helped Hong Kong through the troubles caused by the overflow of the Cultural Revolution. UK government files declassified in 2001 show that, at the time, Cater had a slightly bizarre and almost direct line of communication to Chinese premier Zhou Enlai, via the then chairman of the Hong Kong Kennel Club, one KC Jay.

At first, Cater was reluctant to accept MacLehose's offer, with rumours swirling among Legco and Exco members and reported in the press that the popular civil servant was heading for private enterprise. Later it was established that he was about to be appointed chief executive of Hong Kong Telephone, an extremely lucrative appointment.

Instead, after the governor used all his powers of persuasion, Cater agreed to accept MacLehose's challenge. He was later to tell friends that it was the only job that could have kept him in public service. It was a task he tackled with customary vigour and it was one to which he was well suited.

One of the men with whom Cater worked closely at the fledgling ICAC was John Prendergast, a counter-terrorism expert, who headed the Royal Hong Kong Police Special Branch and who had worked with Cater on Trench's secret committee.

Called out of retirement in Malta, Prendergast returned to Hong Kong to become the hammer of the ICAC. The pair went to work with a will. Their powers included laws which made it an offence for a civil servant to live above his or her means without explanation, or to have more money than could be explained by their official salaries.

Prendergast used these powers with enthusiasm, arresting many policemen with whom he had served. In 1975, Godber was jailed after his extradition from England back to Hong Kong. What was achieved under the ICAC in the five years that Cater was in charge had changed Hong Kong forever.

After looking back on his first 12 months with ICAC, Cater cautiously toted up some success. The most visible achievement was the enthusiastic support the ICAC got from the public. There had been 7,000 complaints. For 683 ICAC posts, he received 8,200 applications, many from young university graduates who wanted to serve with 'Mr Clean'.

By February 1974, he said that the coming two years would see the crunch; that was his deadline for wiping out the well-organised corruption syndicates that had run much of the police force and many other government agencies.

Although wooed eagerly by private enterprise after his five-year ICAC stint ended, Cater decided to remain in government, and in 1978 Governor MacLehose made him Chief Secretary, a job in which he was able to implement many of the social policies he had long advocated since coming to Hong Kong as a 23-year-old Royal Air Force squadron leader at the end of the second world war.

After leaving the RAF, he was attached to the civil affairs unit of the British military administration and fell in love with a city picking itself up from a cruel and devastating occupation.

His first job, in 1946, was as a cadet officer with fisheries, and he was to retain an admiration for the hard-working fishing communities. After he became director of the Agriculture and Fisheries Department, he continued trying to improve their living standards by introducing new technologies such as radar and modern trawlers paid for with financing schemes he helped to devise.

As the tear gas wafted away and peace returned in 1968 after the upheaval of the Cultural Revolution, he was posted for two years as executive director of the Trade Development Council. His energy and un-bureaucratic handling of trade-boosting activities gained him much community attention, particularly from business leaders.

Back in the civil service, he was made Director of Commerce and Industry and sat on the Legislative Council. Popular with both press and public, he was a noteworthy Secretary for Information in 1972, blowing a lot of cobwebs out of stuffy government procedures.

At the Government Information Service, before his appointment to ICAC, Cater instructed staff to answer press queries honestly and swiftly. Instead of being an enemy to reporters, his aim was to make official information channels an aid in telling the public what their government was trying to do.

After his success at the ICAC, he loved his job as Chief Secretary, for which he was made a Knight of the British Empire (KBE) in 1979. He saw his role as helping to shape a fair and just society, by providing housing, education, transport, social welfare - the bones and muscles of a decent community - particularly for lower and middle income earners, who, he said in 1981, had not got a fair share of Hong Kong's economic cake.

Overwhelmingly, they had contributed to the city's success but a vast gap still existed between rich and poor. 'This is an area in which we must do much more,' he said.

Cater retired from government in 1985 and was swiftly recruited by China Light & Power, which had gone into a joint venture over the border to establish the nuclear power plants at Daya Bay. Cater became head of the Hong Kong Nuclear Investment Company, which was responsible for monitoring construction at Daya Bay.

A statement issued by his family described Cater as 'a true friend and servant to the people of Hong Kong throughout the 56 years he worked there'.

He is survived by his wife, Peggy, a son, two daughters, a daughter-in-law and son-in-law, four grandchildren and two step-grandchildren.