The estimated cost of the HS2 line from London to Birmingham has ballooned to as much as £66bn, the scheme’s executive chair has told MPs. Jon Thompson told the transport select committee on Wednesday that the current estimate for the first phase of the line could add “between £8bn and £10bn” to the current top-end estimate of £56.6bn. The discrepancy in estimates is because the current £56.6bn price tag the government and HS2 have been quoting is in 2019 prices and does not reflect the jump in inflation after the coronavirus pandemic and Russia’s invasion of Ukraine. Thompson’s testimony comes only months after Rishi Sunak announced at the Conservative party conference in October that he would be axing the planned HS2 line north of Birmingham, citing cost concerns as the driving factor. The cost of the high-speed rail project has risen repeatedly in the last decade, with the line from London to Birmingham forecast to cost £19.4bn in 2013. Since then there have been a number of revisions, including the last one in November, where …