Herbert Smith has capitalised on its relationship with Severn Trent to win the role as lead counsel on the water company’s planned £1bn demerger and float of its UK waste disposal business, Biffa.

The company announced its plans last week to float the waste recycling and landfill business on the London Stock Exchange before the end of the year, with analysts predicting the company would enter the FTSE 250 index, raising as much as £1.3bn.