The joint endorsement of the review into industrial disputes by the Conservative's Francis Maude and the Liberal Democrat's Vince Cable has suggested renewed coalition tensions on the main target of the inquiry.
Mr Maude said the review would chiefly examine: "Allegations about trade union industrial intimidation tactics, including attempts to sabotage businesses supply chains and harass employers' families."
Mr Cable, though, stressed the review would examine wrongdoing on both sides of industrial disputes.
He added: "There are rogue unions but there are also rogue employers, some of whom have in the past engaged in illegal tactics like blacklisting."
More top news
Watch the amazing moment a cyclist in Russia escapes being killed as a truck and car collide at high speed.
Cameron may have wrong-footed Labour, but there may also be serious rumblings from his own backbenchers, if he wavers on England's future.
Conservative MP Damian Collins believes a recent investigation into corruption at FIFA could result in criminal charges