Sources say firm is asking for more than £1bn in row that could put pressure on two countries’ relationship

• Business live – latest updates

The Chinese owner of British Steel has started a formal process under an international treaty to win compensation from the UK government over its decision to nationalise the Scunthorpe steelworks.

Jingye Steel said it would seek to recover money via China’s bilateral investment treaty with the UK, after more than a year of negotiations over the size of any payout. The dispute could put pressure on the relationship between China and the UK.

Protectionist measures will deal blow to country’s budget as it defends itself against Russia, says Metinvest chief

New EU limits on steel imports could destroy Ukraine’s industry and deal a big blow to the country’s budget as it defends itself against Russia, according to the head of its biggest steelmaker.

Yuriy Ryzhenkov, the chief executive of Metinvest, said the new EU quota system due on 1 July could “kill the Ukrainian steel industry”.

Government urged to help speed up vital industrial project amid growing alarm over National Grid delays

• Business live – latest updates

Trade unions have called for the government to intervene to speed up Tata Steel’s connection to the electricity grid in south Wales, after the company said its new furnace would be delayed by up to a year.

Tata Steel last month told investors that National Grid had said it would face a six- to eight-month delay. That could stretch to 12 months amid unexpected engineering difficulties.