The company, led by Sir Martin Sorrell (pictured), reported a fall in revenue of 2.0%, compared with -0.8% in the second quarter.

Like-for-like net sales dropped by 1.1% in the third quarter – an improvement on the 1.7% fall recorded in Q2.

While Q3 reported revenue was up 1.1% at £3.65bn, ‘constant currency’ revenue fell by 0.4%.

Geographically, revenue growth in the third quarter was stronger in the UK.

The revised forecast, which comes two months on from a previous downgrade, indicates like-for-like revenue and net sales growth to be broadly flat for the year, while the operating margin is also expected to be broadly flat on a ‘constant currency’ basis.

The fall in revenue comes at a time of uncertainty for the advertising industry, as FMCG companies lower their marketing spend due to concerns over effectiveness.