The report, quoted by Reuters Newsagency, said the core British operations of Jaguar Land Rover, which is owned by India's Tata Motors, swung to a net loss of 673.4 million pounds (US$1.11-billion) last year.
This was a change from a net profit of 641.5 million pounds in 2007 under previous owner Ford Motor Company, according to accounts filed with Companies House, in London, last week.
News of the loss comes as the carmakers and Tata Motors strive to conclude talks with the British government over short-term financing.
However, the Financial Times, quoting a person briefed on the matter, reported that the British government was prepared to offer Jaguar Land Rover a guarantee for a 175 million pound commercial bridging loan.
The report said Tata was pushing for a 12-month term for the loan, while the government wanted six months and board representation.
Tata Motors last month said the Jaguar Land Rover unit it bought in 2008 posted a loss after tax of 306 million pounds for the 10 months of the fiscal year to March 2009 as the global recession crippled car sales, primarily luxury and sports utility vehicles.