LONDON (AP) — The British government’s rail policy was thrown into chaos Wednesday after it canceled a disputed contract to run one of the country’s busiest lines following the discovery of “unacceptable mistakes” in the way it awarded the franchise.

The announcement is a partial victory for the line’s present operator, Richard Branson’s Virgin Group, which lost out on the 13-year contract to run the west coast London-to-Scotland service in August to rival operator FirstGroup.