Tasked with gathering over Rs 6,87,715 crore (or nearly $168 billion) as revenue receipts in 2008-09, the two agencies � the Central Board of Direct Taxes (CBDT) and the Central Board of Excise and Customs (CBEC) � will be headed by a succession of bureaucrats with unusually short tenures.

Consider this: incumbent CBDT chairman R. Prasad, who was given a month's extension in view of the Budget, will retire at the end of this month after five months at the helm, just like his immediate predecessor.

From April 1 onwards, the CBDT will see three chairmen in quick succession. P K Misra will have a month's tenure, followed by R S Mathoda with two months and N B Singh with seven months.

Thereafter, Sunita Kaila is slated to head the board for two months ending March, 2009. Once Kaila, who will be the only one of these four chairpersons to participate in making Budget 2009-10, retires, a fresh round of musical chairs will begin.

The situation is only slightly better at the CBEC. Incumbent chairman S K Shingal is retiring at the end of this month after a nine-month tenure (his predecessor VP Singh was better off � he was in situ for 12 months).

The next in line is P C Jha, who is expected to have a term of 14 months. It is harder to predict things after that.

The last time anyone had a decent tenure as CBDT chairman was Ravikant, who was appointed in 1997 and was in the chair for three years.

But this appears to be a tradition of sorts. Since its inception in 1964, the CBDT has had only four chairmen with three-year tenures.

Over the past decade the turnover at the top has increased, leading to tenures of 30 and 60 days, which do not allow an officer to make any real difference.

"Officers in the last month of service are generally busy completing formalities and settling their pension details and so on," said a senior Indian Revenue Service officer.

While the short tenures are a direct result of the government following the principle of seniority, the fact is that over the years fixed tenures for bureaucrats have been institutionalised in various arms of the government including key secretary-level positions.

The need for stability at the top is critical in an election year. It is these two agencies' tax collection efforts that will provide the government headroom for additional social expenditure and political largesse in the form of farm debt waivers.

But the short tenures mean that journalists tend to ask CBDT and CBEC chiefs all sorts of questions except about their vision. The reason is not hard to fathom.