Hong Kong’s leading pollster has announced he is branching out on his own, ending a 28-year association with the city’s oldest university.Dr Robert Chung Ting-yiu, the director and founder of the public opinion programme at the University of Hong Kong, said the opinion poll institute would become an independent body this summer.But both Chung and the university said there were practical rather than political reasons for the decision to end the programme, which has been criticised in the past…