Commercial broadcaster ITV is expected to report the first fall in advertising revenue in 18 months this week.

The Guardian reports that the broadcaster will report a fall in advertising revenue despite having last year witnessed a revitalisation in TV advertising, partly due to last year’s World Cup, which led to an increase of 16% for 2010.

The first quarter is expected to see a rise of 12% year-on-year, with April having increased by 6%, however May and June are expected to witness a decline of at least 7% and 20% respectively.  These will be the first falls in advertising revenue for the company since the end of 2009.