Your leader column (9 May, page 3) reports that the first year for gathering figures for projects completed on time was 2001.

In fact between 1991 and 1995 the Treasury collected progress reports on more than 3,400 developments. The results were published in the Treasury’s 1996 report on procurement to the prime minister. The survey assessed the extent that cost and programme had exceeded estimates given at approval for implementation and were presented under four types of construction: hospitals, buildings, civils and roads.

The average overrun on cost ranged from 11.3% to 17.7% and for time by 6% to 8.6% except for 1990/91 when the average was 25.6%.

Incidentally, the documentary evidence to back up the claim that 46% of projects were finished within budget and 36% completed on time in 2001 should be published.