The arrest in Canada of a top executive of Huawei, the Chinese telecoms group, marks an alarming escalation in the trade and technology transfer dispute between China and the US even if ostensibly its cause is unrelated.

The detention of Meng Wanzhou is certain to complicate efforts to repair relations between the world’s two largest economies. Concern over the implications for the global economy were reflected in market jitters on Thursday, when stocks worldwide extended their recent decline.

Ms Meng, Huawei’s chief financial officer, was picked up during a layover in Canada following an extradition request by the US for alleged breaches of Iran sanctions. China might weather penalties and fines on Huawei should allegations of sanctions busting prove substantive. It is unlikely to take this kind of action on the chin.