There have been moments in history when great leaders have found it necessary to overlook heinous crimes in order to preserve strategic alliances and further greater interests. The alleged killing of Jamal Khashoggi is not one of those moments.

The prominent Saudi commentator has not been seen since he entered the Saudi consulate in Istanbul more than two weeks ago. Details leaked by Turkish officials suggest that he was killed shortly afterwards in the most blood-curdling manner. If Turkish accounts prove accurate — and officials have claimed to have audio, video and other evidence to back them up — there can be no holding of noses. For all Saudi Arabia’s geo-strategic clout, the consequences must be serious.

Western countries have stood united in castigating President Vladimir Putin for Russia’s attempted murder of the former spy Sergei Skripal and his daughter on UK soil. They acted in unison to sanction Moscow even before evidence established the Kremlin’s guilt beyond reasonable doubt. The west must be equally resolute in responding to Riyadh if their agents are found responsible for Mr Khashoggi’s murder, if Saudi guilt is confirmed. To do otherwise would be to invite autocrats across the world to bump off their critics and avert any blow-back with improbable alibis.