London — British Airways flight attendants will walk out next week after the carrier declined to extend their right to strike in return for renewed pay talks following the rejection of the latest offer, according to the Unite union. So-called "mixed fleet" cabin crew, who work on both short-and long-haul flights from London's Heathrow airport, will take action for 48 hours from January 10, the labour group said. Unite had scrapped calls for a walkout over the Christmas and Boxing Day holiday after British Airways (BA) proposed a new pay deal in talks at the UK's Advisory, Conciliation and Arbitration Service (Acas). Staff voted to reject the offer and the company declined to extend the strike mandate, the union said. BA said it aimed to ensure all customers reached their destinations during the planned disruption. It added that Unite could have extended its strike rights via a fresh ballot, and that there had been no approach about talks since the Acas negotiations ended. About 2,50...