Britain's TV ad market looks set to decline in March -- though executives are struggling to explain why.

Television adspend has risen over the first two months of the year, but early reports suggest March will be down by around 4% year-on-year, with all TV stations taking a hit.

The sudden downturn appears especially perplexing given that the Easter bank holiday weekend falls in early April. Traditionally, advertisers raise their spend in the weeks ahead of this break.

"Everyone's scratching their heads wondering why it is so poor," declared John Overend, investment director at PHD. "It should be good because of the early Easter."

The TV ad market rose 2% in January, and is on course for a 4% rise in February. Terrestrial network ITV is doing particularly well this month with a 5% increase. However, early indications suggest it will be one of the hardest hit next month, and its share of TV advertising may fall below 50% for the first time.

Data sourced from: BrandRepublic (UK); additional content by WARC staff