The figure is 1.3 percentage points more than what was forecast, and represents the strongest Q1 growth in three years, despite wider economic and geopolitical uncertainty.

The ad spend forecast for the full year has been revised to 4.8% growth, while the forecast for 2019 has been upped to 4.5%.

Radio advertising had a robust quarter, up 12.5% since the first quarter of 2017. Internet advertising grew by 10.8%, and mobile grew by 26.5%.

TV advertising also continued to see positive growth ( 5.0%), while out-of-home spend grew by 5.3%.

Search advertising, meanwhile, now represents almost three in 10 pounds of UK ad spend – an increase of 1.8 percentage points in the past year.

Stephen Woodford, chief executive at the Advertising Association, said: "UK advertising continues to show steady growth with more businesses investing more spend in advertising. If the government can secure a good outcome from the Brexit negotiations and introduce a business-friendly immigration policy, we should continue to see sustained UK market growth and continued export success for advertising."

James McDonald, data editor at Warc, added: "The UK’s advertising market has grown ahead of expectations in each of the last four quarters, and our projection for 2018 growth has been upgraded by a two percentage points since the start of the year on the back of sterling results across the media landscape."

The quarterly expenditure report includes the AA/Warc’s quarterly survey of national newspapers, regional newspaper data collated in conjunction with Local Media Works and magazine statistics from Warc panels. Data on other media channels is compiled alongside trade bodies and organisations including the Internet Advertising Bureau, Outsmart, Radiocentre and the Royal Mail.