Jingye, the Chinese former owner of British Steel, has demanded compensation from British taxpayers after the firm was brought into the state's hands last week.
The Government assumed operational control of the steelmaker last year after Jingye threatened to shut down the vital blast furnaces at its Scunthorpe plant.
The furnaces are the last of their kind in Britain which still make "virgin" steel.
In a statement on Chinese platform WeChat, Jingye warned the nationalisation had damaged the British Government's credibility and had panicked international investors.
"The UK disregarded Jingye's continuous investment and significant contribution and was only willing to provide almost zero compensation," the firm frothed.
It also demanded that Labour stop "trampling on international investment rules".
Jingye said it had started negotiation procedures under investment agreements agreed between the UK and China.
And it vowed that all options were on the table - including pursuing international arbitration.
The firm also said it would represent British taxpayers in holding the UK Government and British Steel's management legally liable.
Jingye failed to clarify how it would handle the case.
An independent assessment will determine any compensation owed to Jingye, the Department for Business and Trade (DBT) said last week.
And Beijing itself weighed in last week, warning that China's communist rulers were "strongly dissatisfied" with the decision.
The Chinese Foreign Ministry weighed warned that the UK's handling of the dispute would directly shape Chinese investors' perceptions of Britain as a place to invest.
"China urges the UK to earnestly respect market principles and the spirit of contract, and find solutions on compensation and other issues acceptable to both sides," the Ministry said.
It added that Beijing backs firms in defending their legitimate interests through legal channels.
More to follow...
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