The census found that IPA agency staff numbers fell from 24,866 in 2019 to 22,188 in 2020, with creative non-media agencies also seeing a 9% fall in employees to 12,298 and media agencies having a 12.1% drop in staff to a total 9,980.

The IPA found that 25.3% of employee departures were attributed in the census to the pandemic, and reached as high as 30.6% in creative and other non-media roles.

The census, which has run annually since 1960, based its findings on a total of 118 survey responses accounting for 132 member agencies, representing 86.1% of the estimated employed base of the advertising industry.

Female employment levels appear to have been more affected by the pandemic than men, the census found, with a 12.8% fall in female staff compared to 8.1% decline in male staff between 2019 and 2020.

The percentage of women in senior positions dropped from 34% in 2019 to 32.4%, according to the census. The gender pay gap for the industry was 22.7% in favour of males, down slightly on the 24.4% gap recorded in 2019.

However, the number of employees from a non-white background rose from 13.7% in 2019 to 15.3% in 2020, although only 6.4% of senior roles were held by non-white individuals.

An ethnicity pay gap of 19.5% in favour of those from a white background was found by the census. This year was the first time the ethnicity pay gap in advertising has been recorded in the census.

There was a 29.4% drop in employees aged under 25 in advertising, the census found, with 3,243 staff remaining.

There was a 22.1% drop in employees over 60, but the overall numbers of employees were much smaller, with 240 before the pandemic began.

Julian Douglas, president of the IPA, said: “With the exception of numbers of people from non-white backgrounds increasing in spite of overall numbers falling, the impact of the pandemic has exaggerated some existing negative trends.

“Talent is equally distributed, opportunity isn't. Now is the time to turn the industry’s good intentions into meaningful actions.”

Leila Siddiqi, associate director, diversity, at the IPA, said: “This year’s census results confirm that the industry hasn’t met the IPA diversity targets.

“We must take heart that while the numbers haven’t changed as much as we had hoped, some attitudes have.

“Right now, we have the unique opportunity to harness this new understanding by adjusting our ways of working and creating a new culture, fit for the current times, that works better for all of us.”