Viacom, one of the world's largest media companies, has predicted an early end to the current advertising slump.

In an interview with the BBC, Sumner Redstone, Viacom's chairman and chief executive, said he expected an upturn before the end of the year.

"I would say it's quite likely... in either the third or fourth quarters," he said.

Over the last few weeks, a series of media companies have unveiled gloomy results and forecasts, as advertising revenue has been badly hit by the collapse in high-tech fortunes and fears of a global economic slowdown.

The biggest casualties on this side of the Atlantic have been Granada and Carlton, which slipped into the red, with advertising revenues at ITV predicted to drop by 9% this year.

Signs of hope

Mr Redstone is not alone in feeling mildly optimistic, however.

Last week Gerald Levin, chief executive of AOL Time Warner, the world's biggest media firm, said the current advertising slump had already bottomed out.

The main cause for optimism, at least in the US, is the hope that the American economy may escape an all-out recession.

Mr Redstone said he "wouldn't use the word 'sick'" to describe the US economy, and argued that recession fears had been overblown.

"We've been hit as much by perceptions as by reality," he said.

Viacom's shares have fallen by nearly one-third since their peak in August last year.