According to figures posted on Companies House, Jack Morton Worldwide's turnover for events held in the UK dropped from £28.47m to £16.66m. However, profit before tax increased by 25% from £1.82m to £2.29m.
Turnover for events based in the UK saw the biggest fall, with events based in the rest of Europe reporting a 35% increase from £18.93m to £25.54m.
In the report, Jack Morton said: "2013 was expected to be a challenging year following significant growth in 2012 due to the stimulus of the Olympics.
"The external commercial environment in 2014 is expected to remain challenging but the directors are seeking growth opportunities wherever possible and have built a strong client base."