LONDON--Engine Group is to buy fast-growing consumer PR firm Mischief, the Holmes Report understands.

According to sources, Mischief will be integrated alongside Engine’s other PR brands, which include consumer firm Slice PR and MHP Communications.

Mischief was launched by former Shine board director Mitchell Kaye in 2006 and won PRWeek’s Consultancy of the Year award last year. It is understood that Shine CEO Rachel Bell also holds a minority shareholding in the firm. In 2010, Mischief’s fee income reached approximately £2m.

Sacha Deshmukh, the Engine board director who heads MHP Communications, declined to comment on the deal, saying that Engine “makes acquisitions all the time.”

Engine has made numerous agency buys in recent years, including Hogarth and Penrose, which were combined with Mandate last year to form MHP Communications. Also last year, the company postponed its IPO.