SPECIALTY retail jeweller Signet Group plc reported an 11.9 per cent increase in pre-tax profit to $111 mn (£58.3 mn) for the half year ended July 29. The company’s total sales grew by 12.1 per cent to $1.54 bn (£810.6 mn), while same-store sales – sales at stores open at least a year – increased by 5.2 per cent.%%The US, which accounts for 73 per cent of group sales, witnessed a 7 per cent increase in same-store sales, while total sales rose by 15.8 per cent to $1.19 bn (£624.9 mn) during the first six months of the year, compared to $1.02 bn (£539.6 mn) in 2005.%%Signet said that trading conditions in the UK remained challenging throughout the first half. UK like for like sales remained unchanged (H.Samuel -1.6 per cent and Ernest Jones +1.8 per cent). Total UK sales increased by 1.3 per cent to $354 mn (£185.7 mn), versus $350 mn (£183.3 mn) a year ago. “The trading environment on both sides of the Atlantic during the important Christmas period will, as usual, significantly influence the outcome for the full year,” declared Terry Burman, the group chief executive.