Royal Dutch Shell has sought to reassure investors that it will soon be able to press ahead with a promised $25 billion share buyback, after doubts over its cashflow overshadowed a surge in full-year profits.

Ben van Beurden, chief executive of the Anglo-Dutch oil group, said that he was “obsessed” with starting share buybacks as soon as possible and was confident that it could afford them, despite reporting weaker-than-expected cash generation that sent its shares down 2.5 per cent yesterday.

Shell, Europe’s biggest oil company, has its headquarters in The Hague and is incorporated in London. It has global operations ranging from drilling for oil and gas to selling fuel at petrol stations.

It said that profits more than trebled to $12 billion in 2017,…