GMI is a monthly composite score of three different measures – marketing budgets, trading conditions and staffing levels. In November, the score increased three points to 57.8.

Confidence rose across the board, Warc said, but Europe exhibited the largest regional rise, up 3.9 points to 59. Asia Pacific and the Americas were both up 3.1 points to 57.8 and 57.5 respectively.

Splitting out the individual measures, it was the markting budget index that showed the biggest gains, up 4.4 points to 56.2 – “suggesting a pronounced increase in planned expenditure,” said Warc.

The trading conditions index gained 3.1 points to 60.9, while the staffing levels index added 1.5 points to 56.4.

Data and journals director Suzy Young said: “The latest GMI data indicate growing confidence among marketers worldwide, with the indexes for both trading conditions and marketing budgets at their highest level since Warc began the survey in October 2011. These results should provide a real boost to the industry.”