Building supplies company SIG has sacked "a number" of members of staff over accounting irregularities which were revealed by a whistleblower earlier this year. The company revealed on February 1 that an investigation by KPMG and Deloitte found it had overstated its 2016 profits by up to £3.7m because rebates from suppliers were booked incorrectly, “in some cases intentionally”. It had also overstated profits by £400,000 in 2015 and by £2.5m in the first half of 2017.