ALLEGATIONS that Hong Kong security forces became violent in yesterday's forced return flight of boat people sparked a tense 10-hour diplomatic stand-off at Hanoi airport. Hanoi refused to accept the last 27 people to resist, claiming Britain and Hong Kong had broken agreements by dragging them down the steps of the plane. More than a dozen of the 85 returnees, including several women and a baby, had fresh welts and bruises after being carried from the plane and pushed on to the tarmac. They sat stranded for hours while angry Vietnamese Interior Ministry representatives demanded explanations on the runway from Hong Kong and British officials. Protracted negotiations involving London, Hanoi and the British ambassador finally ended at 8 pm Hong Kong time with apparent agreement from Hanoi to take back the final 27. The Royal Brunei Boeing 767 charter was allowed to leave within minutes of a safety deadline which would have grounded the plane and crew in Hanoi overnight. Vietnamese officials warned further talks could be needed before another forced repatriation flight was accepted. The next flight is planned for October 24 and there are now questions over what to do with the 63 remaining detainees at Victoria Prison. 'This is just unacceptable. The Hong Kong and British side did exactly what they said they would not do,' one senior Interior Ministry official said. 'They broke all agreements and used force . . . this was entirely unacceptable. We told them to stop and they went ahead and continued to use force, we had no choice but not to accept the last returnees.' The 35 men, 20 women, 16 boys and 14 girls, most of them detainees for at least six years, were taken mainly from High Island Detention Centre, the scene of violent struggles last Thursday. British and Hong Kong officials refused to comment, but sources confirmed force had been used by police and Correctional Services Department in the 'interests of safety'. The last band had to be dragged off the aircraft as they were 'dangerously' blocking the stairway of the plane, one official said. 'We waited and gave them every chance, and then we used minimal force,' the official said. Returnee Nguyen Thi Ngan, 26, displayed welts on her neck and arms which she claimed were administered on the plane after landing. Her six-month-old daughter Ly had a bruise on her chest the size of a tennis ball. Finger marks were clearly visible. 'It is just what we have come to expect in Hong Kong. They beat and cheat us and they do it even as we are leaving,' she said. 'They grabbed my baby out of my arms.' The confusion started 20 minutes after the plane landed when the first group of about 10 men, women and children launched a noisy sit-in on the exit stairs. Other returnees filed peacefully down the front stairs but the flow slowed as another group joined the protest, some weeping and others shouting insults at Hong Kong officials over the harsh treatment. There was a similar confrontation on June 14 on another forced return flight when Hanoi stopped the extraction operation citing violence.