Allan said there had been "very robust discussions" between Tesco and a number of suppliers, and referenced last year's spat with U.S. food giant Kraft HeinzKHC.O. LONDON, Jan 23 (Reuters) - Britain's farming union accused the boss of Tesco TSCO.L, the country's biggest supermarket, of living in a "parallel universe" after he said food companies may be using inflation as an excuse to hike prices further than necessary. Official inflation data for December published last week showed food prices 16.8% higher than a year earlier, the sharpest increase since September 1977, led by eggs, milk and cheese.