The London office of Publicis Groupe's ZenithOptimedia has backtracked on its earlier predictions for UK advertising expenditure in 2005.

Confounded by declining advertiser demand during the year's first half, the media network admits it is "significantly revising" its original forecast of 4.9% UK adspend growth.

Predicted growth for this year is revised downward to just 2.9% - a differential of almost sixty per cent. How could this highly regarded media agency have got it so wrong, many wonder?

As WAMN never tires of pointing out, forecasting advertising expenditure is a risky business - especially in the environment of hype, half-truths and propaganda that epitomize media budget posturing on all sides of the advertising spectrum.

Zenith cites several factors influencing its reassessment. In particular it fingers the nation's biggest advertiser COI Communications, the administrative interface between the British government and its roster of advertising and marketing agencies.

It is traditional practice for the government to cut back dramatically on all advertising in the run-up to a general election, as indeed was the case in March, April and May. And unlike the USA and other nations, there is no compensatory party political advertising on the prime medium - television.

This, Zenith claims, was exacerbated by the effect of an early Easter holiday on retail spending. Nor was expenditure boosted during H1 by any major sporting event.

All of which, including the election, was eminently predictable.

The agency's revised growth forecast of 2.9% overall assumes only a modest increase in TV advertising (1.5%), the press (+1.3%) and radio (+1.1%). Internet advertising, however, is expected to surge year-on-year by nearly 30%.

Data sourced from Media Week (UK); additional content by WARC staff