Whitbread has reported sales growth of more than 10 per cent for second quarter, boosted by brisk business at its Costa Coffee and Premier Inn chains.Total sales increased 10.8% in the 11 weeks to August 15th from a year earlier and revenue at outlets open a year or more was up 2.1%, the group said in a trading statement. Total sales were up 17.7% in London.Andy Harrison, Chief Executive, said: "We are on track with our annual plan and our ambitious five-year growth milestones. Combined with our emphasis on returns, this growth should continue to create substantial shareholder value."Like-for-like sales rose 3% at both Premier Inn and Costa. Sales at Whitbread's restaurants, which are less focused on London, reduced by 0.2%.Whitbread reports its interim results on October 22nd.SF