(Adds AGM vote)
LONDON, June 25 (Reuters) - Martin Sorrell's WPP, the world's largest advertising group, said trading had improved in the last two months due to strong growth in the United States and Britain.
The firm said revenue on a like-for-like basis was up 7.6 percent in the first five months of the year, compared with the 7 percent rise recorded in the first three months.
In other positive news for the British company, shareholders backed its remuneration policy at the firm's annual general meeting, with 82 percent of investors who voted backing the plan.
That follows complaints in previous years over Sorrell's salary, which last year jumped to 30 million pounds ($50.9 million), boosted by a performance-related scheme.
WPP, which has been outperforming its rivals in recent months in terms of organic growth, has been lifted by the collapse of the planned merger between rivals Omnicom and Publicis, which has enabled Sorrell's firm to poach clients.
"Following the group's record year in 2013, 2014 has started stronger and similar to the final quarter of 2013," it said.
Shares in the group were down 0.5 percent in midday trading. ($1 = 0.5892 British Pounds) (Reporting by Clare Hutchison and Kate Holton, editing by James Davey)