Morgan Stanley and Rothschild have clinched a £5.8bn (€8.6bn) sell-off for National Grid Transco, the UK utility, with the sale of four regional gas distribution networks in one of Europe's biggest deals this year.

The units were sold at a 20% premium to valuations last year by Ofgem, the energy regulator, and will allow National Grid Transco to return £2bn to shareholders, worth 65p per share or 14% of the UK listed company's market capitalisation. The utility company, which has taken a year to complete the disposals, will also repay £2.3bn of debt.