British Airways refused to rule out more flight cancellations on Sunday as it struggled to cope with a massive backlog of luggage at London Heathrow airport's new multi-billion-pound Terminal 5. BA, which has sole use of Terminal Five (T5), also confirmed that it has scrapped 37 of its 331 flights that were planned to and from the facility on Sunday. The airline was also working to return about 15,000 pieces of luggage to their rightful owners – and has warned that passenger delays and cancellations at the terminal will last into next week. T5 has been blighted by logistical troubles ever since it opened to much fanfare on Thursday, with problems revolving around its luggage retrieval system. “We are still planning to operate 85 percent of flights, and as far as I know there are no extra flights being cancelled,” a BA spokeswoman said Sunday. “It all depends on the baggage system. The bag situation is the same as it was – there are 15,000 to be sorted through. We have put on extra staff to work through them all and repatriate them. “At the moment the situation is that there are no more cancellations planned.” When asked if BA would be cancelling any more flights, she added: “I could not make that promise.”Long-haul flights on Sunday are operating as scheduled, but some domestic and European flights have been ditched from T5, according to a company statement. “We are endeavouring to do everything we can to get the operation back to normal,” the spokeswoman added. Heathrow's brand new Terminal Five, which cost 4.3 billion pounds ($8.7 billion) to build, has been mired in controversy ever since it opened on Thursday. The spacious terminal was meant to be a jewel in the crown of British airports operator BAA, which owns and operates Heathrow, and British Airways, which enjoys exclusive use of the facility. __