Sullivan & Cromwell has been drafted in to advise Microsoft on its landmark $44.6bn (£22.bn) attempted takeover of internet giant Yahoo after New York rival Simpson Thacher & Bartlett was conflicted out.

Simpson Thacher this week confirmed that it had been forced to withdraw from the mandate due to a conflict which could not be resolved. The firm had initially been handed the lead role for Microsoft, as reported by legalweek.com on 4 February.