A new $52.8 billion (£33 billion) line is set to improve links between London and major cities in northern England, but it has been met with opposition from critics who fear it will blight the countryside.
Only Fools and Horses star Jason, who resides in the Chiltern Hills in England, reveals he has similar reservations and admits he is worried about mounting costs for the project.
He tells Britain's Daily Telegraph newspaper, "We live in the Chilterns and it's going to be so damaging. The line will slice right through the Chilterns and there's going to be huge opposition.
"What makes me laugh is the figure they gave of £33?billion. You know what will happen. It will be like all these projects. After a few years, they will say the cost has gone up to £40?billion, then it will be £60?billion. Eventually it will be £90?billion and, when they are questioned about it, they will say, 'Oh, that was 10 years ago. The costs have gone up so much since then.'"