LADY DUNN last night used her platform in the House of Lords to urge Legislative Council members to back Governor Chris Patten over the Court of Final Appeal. She made a rare appearance in the House to tell peers the agreement on the court had been 'overwhelmingly welcomed by the Chief Justice, local and international businesses . . . and the majority of Hong Kong people, so it's a remarkably successful agreement'. For the British Government, Foreign Office Minister Lady Chalker said Lady Dunn 'knows better than any of us about the great difficulty in which Hong Kong' was placed by China's refusal to implement the 1991 agreement on the court. Lady Chalker told Lord Willoughby de Broke, who raised the issue, that the agreement on the court was in accord with the Sino-British Joint Declaration. She claimed in further questioning over doubts in Hong Kong about the court deal that China would not have the jurisdiction to decide what was an 'act of state'. In answer to Labour party spokesman Lady Blackstone, Lady Chalker said the aim of the new deal was 'to prevent a legal vacuum before 1997'. Lady Chalker said the new deal would ensure continuity of the law throughout the handover. 'I'm sure the House of Lords will see the sense of that,' she said.