Aggregate Industries, the UK-based construction products group, has speeded up the timetable for its takeover by Holcim and could announce a pounds GBP1.8bn agreed deal as early as Thursday. Holcim, the world’s second largest aggregates and cement group, started due diligence checks on Friday and is working through the weekend, with both sides hoping to agree a full takeover by the end of the week. The Swiss firm already has a 15 per cent stake in Aggregate and will return to the market this week to buy up a further 15 per cent. If the deal goes through as expected, Peter Tom, the chief executive of Aggregate will make pounds GBP30m from the company he has built up over several decades from a small family firm.  Peter Tom and the rest of the Aggregate management team are likely to be retained by Holcim .