Advertising and PR firm WPP has snapped up fellow London-headquartered design agency Design Bridge Limited as it revealed concerns about like-for-like sales and its full-year growth.

The global advertising firm, which employees nearly 2,000 people across its global offices, has acquired the design house, which itself has studios in London, Amsterdam, New York and Singapore, and will operate it as a separate brand under the WPP Group banner.

The value of the acquisition is undisclosed, but WPP has said that Design Bridge brought in revenues of approximately £40m for the year to 31 December 2016 with gross assets of around £28m. The agency has previously worked with the likes of AkzoNobel, Diageo, Mondelez and Unilever.

WPP announced the acquisition at the same time that it released its interim results for the first half of 2017 which showed profits before tax rising to £779m, an increase of 83% on H1 in 2016 or a 52% increase in constant currency.

However, the advertising group warned that like-for-like sales were falling and that its growth this year was likely to be below expectations.

The news caused WPP’s share price to drop over 10% in early trading.

It comes after the business was one of the most high-profile global firms to be hit by the NotPetya ransomware cyber attack in June which brought down much of its computer network and systems across a number of its business.

However, despite a weaker performance in June and July, WPP claims that it has suffered negligible financial fallout from the event and that the majority of its systems were restored within one week of the attack.

In its interim results, it stated: “Although there was some delay to certain financial processes, the Group did not experience any significant loss in revenue from clients or of data and believes that the cyber-attack cannot be blamed for the weaker performance in June and July.

“Whilst it is virtually impossible to prevent 100% of attacks of this nature, further measures are being taken to assess and strengthen our controls and recovery procedures.”