Europe's largest high-speed rail operator has predicted that domestic air travel in the UK will lose millions of passengers to a 250mph train service if an ultra-fast network becomes a reality.

During pilot tests in Singapore, forecasts made across 500 urban locations accurately predicted traffic volume 85 to 93 percent of the time and vehicle speed 87 to 95 percent of the time.

This week the IMF predicted that global GDP should expand by 4.8% this year—slower than in the boom before the financial crisis, but well above the world’s underlying speed limit of around 4%.