Business publisher Informa posted a sharp fall in profits as tough conditions at the group's events division offset resilience in the publishing arm.Revenues in the six months to June 30 climbed to £636.3m from £627.6m, but pre-tax profits slumped to £32.2m from £60m.While exhibition revenues climbed by 3%, sponsorship fell by 5% and delegate revenues slid by 31%, Informa said."We are experiencing the most severe downturn ever in this area," Informa said. "Trends of the past eighteen months have continued with our exhibitions and larger conferences proving more resilient than the smaller conferences and training courses."Revenues at the publishing division, which includes the shipping newspaper Lloyds List, climbed by 13% from the previous year to £322m."Our subscription based products provide a degree of resilience and we continue to develop new workflow solutions for electronic distribution in niche product areas to provide our customers with "must have" information," the firm said.Only 3% of group revenues come from advertising, the firm said.