M&C Saatchi, the ad agency founded by brothers Charles and Maurice Saatchi, has reported a like-for-like revenue increase of 11% to £104.4m in 2008 and said that overall trading in the first quarter of 2009 has been in line with management expectations.

The ad agency network, which believes its mantra of "brutal simplicity" is well tailored to help it weather the downturn, reported a headline profit increase of 18% to £14.1m before tax, excluding factors such as goodwill charges.

The group, which has clients including NatWest and the government's anti-obesity campaign Change4Life, said that it reported significant revenue growth in all regions except America. Headline operating profit increased by 34% to £13.7m last year while operating margin increased to 13.2%.

"M&C Saatchi delivered a solid performance in 2008, in spite of the difficult economic environment. We enjoyed significant revenue growth in most regions ... after a particularly strong first half, market conditions became increasingly challenging through the year," said the M&C Saatchi chief executive, David Kershaw.

"Looking ahead we are confident that the business is in good shape. The ongoing economic uncertainty and limited visibility mean we remain cautious. Against that backdrop we will keep a tight focus on controlling costs."

M&C Saatchi, in which Matthew Freud took a 3.3% stake last month, said that the deteriorating economic conditions had particularly hit its operations in Spain and the US, and its strategic consulting firm Clear Ideas, which it acquired in 2007.

In the UK, overall revenue grew by 14% to £60.3m year on year at a like-for-like growth rate of 8.4%. Organic revenue – from ongoing business, excluding acquisitions and disposals – grew by 8.4% year on year.

The company reported that there was increasing pressure on fees and margins in the last quarter of 2008 "but no significant reductions". Headline operating margin in the UK increased to 16.5% but came "under pressure" in the fourth quarter.

M&C Saatchi said that overall its European operation had performed well, with revenue increasing by 70% to £10.3m. Growth was fuelled by its Paris office, which reported a 68% revenue increase on the back of launching digital and corporate PR services, and a 25% increase in revenue in the smaller Berlin operation.

The achilles heel in Europe was the Madrid office which had a "very difficult year", leading the agency to rule out increasing its stake in the associate business beyond the current 25%.

Offices in the Australia and Asia region performed well, reporting a like-for-like revenue increase of 14%. The Australian office continues to dominate M&C Saatchi's operations across the region, accounting for 66% of revenue and 73% of profits.

M&C Saatchi said that like-for-like revenue growth in the US fell by 15% year on year.

The US operation, based in Los Angeles, endured a second difficult year, reporting a marginal decline in revenues to £4m and a drop in operating margin from 14.1% in 2007 to 7.3% last year.

M&C Saatchi said that from September, when the economy started to "bite" in the ad industry, the agency had reduced its global headcount by around 5%, about 50 posts, to about 1,000 staff.

The finance director, Jerry Wales, said that the company had not had to consider any more cuts in the first quarter this year, but would reduce headcount if the agency's performance deteriorated later.

• To contact the MediaGuardian news desk email editor@mediatheguardian.com or phone 020 3353 3857. For all other inquiries please call the main Guardian switchboard on 020 3353 2000.

• If you are writing a comment for publication, please mark clearly "for publication".