Two of Britain’s biggest recruitment companies have warned that uncertainty created by Brexit, protests in Hong Kong and the US-China trade dispute will hit their profits this year.

PageGroup, the UK’s second-largest recruiter, said rising fears about Brexit had made companies less willing to hire workers and potential candidates wary about moving jobs. It said uncertainty had affected the market for jobs at all levels.

The company was the biggest faller in the FTSE 250, with shares down 12% to a near three-year low of 367p, after it said annual operating profit would be between £140m and £150m compared with expectations for £156m. Its rival Robert Walters predicted no increase in profit this year.

Business also deteriorated in China, where both companies have expanded. They blamed uncertainty created by protests in Hong Kong and Donald Trump’s trade war with Beijing. PageGroup’s profits in China fell by 24% in the third quarter, while problems in China restricted Robert Walters’ growth in the Asia Pacific region to 3%.

Both companies reported falling UK profits over the period. PageGroup’s UK profit fell 4% to £33.8m in the three months to September and Robert Walters’ dropped 11% to £24.3m.

Steve Ingham, PageGroup’s chief executive, said: “In the UK, heightened Brexit-related uncertainty is expected to remain as we approach and go beyond 31 October … In greater China, confidence in mainland China continues to be affected by trade tariff uncertainty and the social unrest in Hong Kong is increasing.”

Ingham said trading was better in the US and elsewhere in Europe but that worsening economic conditions suggested business there could slow.

Robert Walters shares hit their lowest point for more than two years, falling 5% to 464p. Shares in Hays, Britain’s biggest recruiter, fell 5% to 135p. Hays, which updates on trading next week, said in August that clients in the UK were putting off hiring workers because of Brexit.