Colleagues close to Assistant Garda Commissioner Tom King yesterday expressed concern about the impact his decision to retire would have on the morale of the force's management. Mr King was seen as the force's brightest management figure. Multilingual and with an M Sc degree in organisational behaviour, he had instituted major improvements in Dublin's police service in just 1 1/2 years.

During his time as head of the Dublin Metropolitan Area (DMA), colleagues said, he had regenerated enthusiasm for policing throughout the ranks. The operations to reduce street drug dealing, improve traffic flow and increase beat work in O'Connell Street were introduced largely at his initiative.

However, according to colleagues, he had become concerned at the prospect of introducing further reforms to policing in the capital. It is understood that he and some other senior officers were becoming frustrated about tackling politically-sensitive issues, such as changing the opening hours of stations, rewarding initiative by hard-working officers, and sanctioning those who were under-achieving.

Senior sources said Mr King had spoken recently of his concern that there was a need for strategic management change over two to three years, but that he was increasingly uncertain if this was possible.

The announcement of his departure was said to have shocked many in the senior ranks who looked to Mr King as a future, energetic leader.

One said: "We can't afford to lose him. If the system could produce three or four like him at this level, his departure could be taken as part of the natural progression but, frankly, there are not enough like him.

"It is quite serious for the people who were working with him in Dublin and whoever comes after will be facing a situation where people will be asking: `Is that Tom's way of doing it?' "

It is understood Mr King was offered a senior position in the private sector in recent months and decided it offered a greater challenge and much better money.

According to one colleague, he had been very annoyed at the decision of the Buckley Report on higher Civil Service pay to cap the salary of assistant commissioner rank. He was said to have been shocked to read recently that an RUC superintendent (a rank two levels below Mr King's) with four years' service is paid more than a Garda assistant commissioner.

If he had decided to serve out the eight years of his career, he could have aspired to promotion to the rank of deputy commissioner, with pay of £59,261, and then to Garda Commissioner, with a salary of £69,673.

His counterpart in the RUC, an officer of assistant chief constable rank, can aspire to a deputy chief constable pay level of £91,740, and a chief constable's pay of £114,675.

RUC salaries are slightly higher than those of other UK forces because of the risk factor. However, the chief constable of one of the larger British constabularies is still paid about £107,000.

The Garda Commissioner and the ESB chief executive both head state-owned organisations with responsibility for about 10,000 personnel. However, the Garda Commissioner earns around £36,000 less than the proposed salary for the new ESB head.

The chief executive of a private company of similar size would be paid many times more than either the Garda Commissioner or the ESB chief executive.

The likelihood of senior gardai being lured into the private sector is increasing with economic improvement. Mr King is the fourth officer to leave a senior post this year.

Three Dublin superintendents, Mr Patrick Fennessy, Mr Patrick King and Mr Bill Somers, took early retirement this year for well-paid security jobs in the private sector. Last year, the former head of the Central Detective Unit, Chief Supt Tom Butler, left the force to become head of security at a major bank.

Such positions can prove very tempting to senior gardai or Defence Forces officers, many of whom have considerable administrative and management qualifications.

The Garda Commissioner, Mr Patrick Byrne, has expressed concern that further good managers could be lost from the force. He is known to be concerned that the decline in Garda pay relative to other public or semistate sectors is having a negative impact on morale in the force.