(TheGrocer) - Off-trade wine sales could slump by as much as 13% in volume over the next few years if prices and duty continue to escalate. That was the warning issued by wine industry experts this week, days after Majestic Wines boss Steve Lewis said entry price-point wines in supermarkets would be hardest hit by price hikes caused by poor harvests. Wine supplier Brand Phoenix, which works with International Wine & Spirit Research analysts, predicted that the off-trade market would fall from 91 million nine-litre cases to around 80 million - or 13% - by 2015. Typical annual UK wine consumption could slump from 24.5 litres per head to 22 litres, added the First Cape owner.