Official returns to the Electoral Commission show that The Conservative Party, which spent heavily in the regional press, almost doubled its budget from £4.5 million in 2001 to £8.1 million this year.
The Liberal Democrats, who attracted rich donors ahead of the May poll, boosted their ad budget from £196,000 in 2001 to £1.6 million, a record for the party. Labour's £5.3 million spend was up slightly from £5 million four years ago.
However, the total spend was still lower than in 1997, when the Tories spent £13.1 million and Labour £7.3 million. Since then, campaign expenditure has been limited by law.
Some party officials still predict a long-term switch to direct mail.
This year saw a marked increase in the use of mailshots. The Tories spent £4.5 million (up from £1.2 million last time), Labour £2.7 million (up from £1.5 million) and the Lib Dems £1.2 million (up from £54,000).
