The best performers of the session on the Investing.com United Kingdom 100 were Halma PLC (LON:HLMA), which rose 13.36% or 314.00 points to trade at 2,664.00 at the close. Meanwhile, BT Group PLC (LON:BT) added 4.33% or 5.60 points to end at 135.00 and Severn Trent PLC (LON:SVT) was up 4.18% or 101.00 points to 2,520.00 in late trade.