A former ballerina who says a knee injury forced her to end her career appeared in court yesterday seeking up to $6 million damages from Hong Kong Ballet Ltd and the now-defunct Urban Council. Ruthanna Lau Sau-yee, 29, said the floor the Hong Kong Ballet hired for rehearsals at the Hong Kong Cultural Centre was too slippery, causing her to tear a ligament during a simple leap. She was left with restricted movement in one leg. As a result of her accident, which happened on September 17, 1994, her professional dancing career was destroyed, Ms Lau's counsel, John Wright, said yesterday. Mr Wright also said the injury prevented the dancer from teaching anything above junior level for a living. It is only the higher levels that are lucrative, the court heard. The Urban Council was named in the proceedings as it was responsible for the upkeep of the rehearsal floor. The council and the ballet company deny liability. Mr Wright said the floor was used at least eight hours a day by the ballet company and several other dance associations. 'The floor was never designed or meant to be used or subjected to such heavy use.' Mr Wright said Ms Lau's situation could be compared to sending rugby players out to play on a pitch frozen into a rough sheet of ice. He said the leap Ms Lau executed at the time of the accident was not a dangerous move if carried out on a non-slippery surface. The Court of First Instance heard Ms Lau had been employed by Hong Kong Ballet Ltd since July 6, 1992, and rapidly rose through the corps de ballet. Mr Wright told the court that had Ms Lau not injured her knee, she would have reached one rank below a soloist within two to three years. The personal injuries case continues before Deputy Judge Edward Woolley.