Martin Sorrell, chief executive officer of WPP group
Martin Sorrell, Chief Executive Officer of WPP Group, oversaw a 15.8% jump in first half profits to £690m (Reuters)

Advertising giant WPP posted a jump in profits in its first half of the year, adding that the UK's Brexit vote will not hamper its plans for growth.

The group, which includes the Ogilvy & Mather and J Walter Thompson agencies, said pre-tax profit in the period jumped 15.8% to £690m ($910m), boosted by an almost 12% lift in sales to £6.5bn.

It said despite the UK's vote to leave the European Union it saw a "continued strong performance" in new business wins, and raised its revenue ratios for its new media and fast growing markets from 35%-40% to 40%-45% over next four to five years.

However, the company was hit by a £122m writedown linked to its investment in a US internet analytics firm comScore.

The group, run by founder and chief executive Sir Martin Sorrell, added that its return on equity in the 12 months to the end of June fell to 15.5% from 15.9% "reflecting the post-Brexit impact of a considerable weaker pound sterling on the group's net assets".

WPP said its "performance in the first seven months of the new financial year has been reasonably strong, as worldwide gross domestic product growth, both nominal and real, seems to have slowed in the second half of last year and into the new year".

Richard Hunter, head of research at Wilson King Investment Management, said that "WPP's reputation as a market darling shows little sign of diminishing. WPP has shown consistency in terms of being fleet of foot in identifying acquisitions, whilst its ongoing push towards digital is beginning to reap rewards."