In a trading statement today (30 April), WPP reported sequential improvements each month during the first quarter.
Revenue in the UK was £251.6bn in the three months to the end of March 2010.
Group revenue in March was up 1%, the first monthly revenue growth year on year since December 2008.
WPP said there had been a change in client attitudes during 2010 and that there had been a shift to calendar budgets focusing on "how to achieve top-line growth, rather than on just cutting costs".
On a like-for-like basis, excluding the impact of acquisitions and currency fluctuations, WPP's group revenue was flat in quarter one 2010, compared with 2009, and in constant currency, revenue was up 0.5%, reflecting the strength of the pound sterling against the US dollar and Euro.
While WPP's business in the USA recovered first with a constant currency growth of almost 4% in the first quarter, the UK arm of WPP was next with a small positive constant currency growth.
In the communications services sector, WPP said branding and identity, healthcare and specialist communications, which includes direct, digital and interactive, have recovered more quickly.
WPP said the direct and interactive networks of Wunderman, OgilvyOne and G2 all showed like-for-like growth and specialist digital companies, including 24/7 Real Media, Schematic, Blue Group and Quasar, showed like-for-like growth of more than 9%.