More than £1.25bn has been spent acquiring property in London to make way for High Speed Rail 2 (HS2), according to a freedom of information request.
The cost of building the new line, which is expected to open between 2028 and 2031, has soared to between £81bn and £88bn.
The freedom of information request from the Local Democracy Reporting Service revealed the total spend on purchasing property in the capital to be at least £1,256,089,849 as of 30 June.
Many of the properties bought to make way for the railway are located in Uxbridge, Northolt, Camden and Westminster.
A spokesman for HS2 said: "Every home, business and piece of land is unique and we appreciate that there may often be different opinions between owners, their professional advisers and HS2 about the value of a property.
"We work with the people affected to reach agreement, recognising the differences in opinion can take time to resolve."
The high-speed rail line is designed to boost the UK's economy by cutting journey times between London and the Midlands and the north of England.