Organic growth was supplemented by the acquisition of the healthcare communications and consultancy business Mash, the group said.

Cello’s business is now split along two lines – Cello Health and Cello Signal, a consumer marketing-focused business line.

Within Cello Health, gross profit was up 13.8% to £35.6m, with headline operating profit of £7.56m – a margin of 21.2% (up from 20.8% the year before).

Cello Signal, meanwhile, increased gross profit by 15.7% to £37.9m. Headline operating profit was £3.87m – a smaller margin of 10.2%. But, as with Cello Health, the margin was up year on year from 9.1%.

“2013 has been a very strong year that has demonstrated the potential of Cello’s strategy to deliver superior performance,” said CEO Mark Scott (pictured). “We are confident that both businesses will continue on their growth paths and deliver a successful 2014 performance for the group as a whole.”