Belgium’s Saverys family is poised to block a full legal merger of tanker giants Frontline and Euronav after more share purchases in recent days.

The owners of shipping firm Compagnie Maritime Belge (CMB) now control 23.99% of compatriot Euronav, 1% short of the 25% needed to thwart the companies’ ultimate ambition of a complete union of their operations.

But Frontline and Euronav can still combine their fleets through a simple majority of 50% plus one vote.