The UK is in talks with China over giving Beijing’s state-owned railway builder a role in constructing the HS2 high-speed rail line.
China’s state railway company said it could build the line in just five years and at a much lower cost, according to a letter seen by Building magazine.
Government officials said “preliminary discussions” had taken place, but no “concrete commitments” had been made.
It comes after Boris Johnson this week approved the controversial scheme.
This was despite an official review warning costs could reach over £100bn, against a budget of £62bn.
Under current plans, the final stretch of the line is not due to be completed until 2040 – although Mr Johnson has said he wants that brought forward to 2035.
However, Building magazine reported that the China Railway Construction Corporation (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.
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.
The CRCC letter, also been seen by the Financial Times, states: “We are certain that we can offer a cost that is significantly lower than the projections we have seen.
“The advantages are too great, in our opinion, too great to dismiss on the basis that there are obstacles to overcome.
“You will find that the Chinese way is to seek solutions, not linger on obstacles and difficulties.”
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.
Supporters of HS2 say it will improve transport times, increase capacity, create jobs and rebalance the UK’s economy.
Once it is built, journeys will be shorter. London to Birmingham travel times will be cut from one hour, 21 minutes to 52 minutes, according to the Department for Transport.
And while it is being built, it is expected to create thousands of jobs and provide a stimulus to economic growth.
A Department for Transport official said: “The DfT is always keen to learn from the experience of others and to consider approaches that offer value for money to the taxpayer.”