Increasing low-cost steel flows from Asia risk making domestic production unsustainable and putting British jobs in peril, Tata Steel UK has told the government, after new tariff quotas sharply raised the volume of certain imports allowed into the country duty-free.

The quotas were designed to shield Britain from a wave of cut-price metal diverted from other markets, imposing duties of up to 50% once ceilings are breached, the Telegraph reported. The enlarged Indian quota is understood to have been a last-minute concession to New Delhi during free trade agreement negotiations.

But their structure has baffled industry insiders. In the metallic-coated galvanized steel category, Vietnam's annual allowance has more than tripled from 51,000 tonnes to 174,000 tonnes, while India's rose from 98,000 to 125,000 tonnes. Tata's Llanwern plant in South Wales produces about 600,000 tonnes of galvanized steel a year, an output now squarely in the path of cheaper imports.

The company is overhauling its operations after shutting the last blast furnaces at Port Talbot, investing in electric-arc furnaces that will melt scrap into "green" steel to meet tightening net-zero rules.

It argues that the environmental standards it must observe in Britain leave it unable to compete on a level field, warning that without changes, the current setup risks overwhelming domestic production to the point where UK manufacturing capacity becomes unviable.