COI Communications spent a record £203.2m on advertising in 2004-05, a rise of £14m on the previous year. Its total marketing expenditure in the 12 months to March was £333.6m, also a record.
The COI spent more than any other advertiser in the first three months of this year, according to Nielsen Media Research. Total adspend for that period was £67.2m, compared with £53.7m for Unilever and £41.7m for Procter & Gamble.
In 2004 it spent less than both companies.
Chris Grayling, shadow leader of the House of Commons, said: 'The fact that spend increased so significantly just before the election demonstrates that Labour is using this budget for its own ends. Labour should stop making taxpayers pay for its propaganda.'
The election was called on 5 April, with a polling date of 5 May. Advertising during the campaign is restricted, and the COI's spend slumped to £5m in April.
A COI spokeswoman said: 'The Phillis Review (of government communications) recommended more unmediated public communications. Tight checks ensure that government ads are not political.'
Leader, page 31.