The deal sees Engine expand into the City and corporate sectors, having already acquired public affairs agency Mandate Communications (formerly AS Biss) and consumer agency Slice.
Last October, PRWeek revealed that Hogarth had begun a search for a suitor (PRWeek, 6 October 2007 ) and the agency had been in talks with Engine since the start of the year concerning a deal.
As part of the acquisition, which does not feature the usual earn-out structure, the six founding Hogarth partners and five Hogarth directors become Engine shareholders. The undisclosed fee was paid via a mixture of cash and shares.
Hogarth said it had a fee income 'approaching £5m' and a client list including PZ Cussons, Sainsbury's Pensions and Carluccio's.
'We had a range of approaches before and during our formal review,' said Hogarth joint managing partner John Olsen. 'But Engine understood the Hogarth culture and with this acquisition we can strengthen out client offering, working with Engine agencies such as Mandate.'
Engine made contact with Hogarth two years ago, just after its formation in 2005. It created Mandate last November after merging AS Biss, which it bought in 2005, and Republic PR (PRWeek, 17 November 2007 ). In October 2005 the firm also bought consumer agency Slice.
'Our intention is to build a high quality, broad-based group of consultancies that are outstanding within their own specialised disciplines,' said Engine chief executive Peter Scott.