The cost to Britain's sovereignty could be "higher than we ever imagined" if Beijing's state-owned railway builder is given a role in constructing the troubled HS2 high-speed link, a Tory MP said.
Britain is in talks with China about the project and the China Railway Construction Corporation (CRCC) has said it can build the line in just five years at a much lower cost than is currently forecast, according to the Financial Times.
Department for Transport (DfT) officials confirmed that preliminary discussions had taken place between CRCC and HS2 Ltd, but added that no concrete commitments had been made.
The DfT said it is always keen to learn from the experience of others and to consider approaches that offer value for money to the taxpayer.
Tory MP Tom Tugendhat, chairman of the Commons Foreign Affairs Committee, told the PA news agency:
Britain needs to think hard about how we partner with countries that don't share our respect for human rights or the rule of law.
Mr Tugendhat earlier told the BBC Radio 4 Today programme that the UK is "in dire need of a proper China strategy", adding:
We are being offered, at extraordinarily generous terms it appears, everything to connect our telephone networks, to connect our cities and to connect our power networks.
Mr Tugendhat, who was an outspoken critic of the Government's decision to allow Chinese tech giant Huawei a role in building the UK's 5G network, questioned CRCC's claim it could build the entire line in just five years.
"The reason why Chinese projects in China are very often so quick is because they don't worry about such minor matters as planning consent or workers' rights," he said.
"It seems extremely unlikely that without really short-cutting any number of labour conditions that it would be possible."
Boris Johnson this week controversially gave the green light for the scheme to go ahead - despite an official review warning costs could reach over #100 billion, against a budget of £62 billion.
Under current plans the final stretch of the line is not due to be completed until 2040 - although the Prime Minister has said he wants that brought forward to 2035.
However, the FT reported that CRCC had written to HS2 Ltd's chief executive last month saying it could build the line by the middle of the decade, for a much reduced price tag.
The letter, first reported by Building Magazine and seen by the FT, states:
We are certain that we can offer a cost that is significantly lower than the projections we have seen.
CRCC has transformed China's transport system, building most of the country's 15,500-mile high-speed network.
However, British officials are said to be sceptical that it could operate in the same way in a democracy with property rights, protected landscapes and powerful lobbying groups.
Any move to give Beijing a further role in the UK's infrastructure would almost certainly prove controversial, after Mr Johnson reportedly incurred the wrath of US President Donald Trump - as well as upsetting many Tory MPs - with his decision to allow tech giant Huawei to supply equipment for the 5G mobile network.
Sim Harris, managing editor at industry newspaper Railnews, said:
It might sound seductive to some people, and they are saying they could get it done in five years, well they probably could if they ignored all British planning law, all third party objections."