Huawei has said it will be “months” before it can provide customers such as BT and Vodafone with full reassurance over the impact of the US sanctions at the heart of an imminent UK government decision that is set to undermine its ability to supply British telecoms companies with new 5G equipment.

A UK security inquiry has raised “very, very serious” questions about whether Huawei can continue with its limited role as a supplier for 5G networks after the US announced sanctions in May, according to Whitehall officials.

Those sanctions, which networks have warned could choke off the supply of chips used in Huawei equipment, are set to come into force in September, leaving some of its largest customers reliant on stockpiles of existing 5G kit which will only last into early next year.