The contractor jumped six places to the top of the 20 best paid suppliers rankings after Network Rail raised its spending by 75% with the contractor compared with previously.

This was driven by Costain’s London Bridge and Reading station upgrades, with it now waiting in the wings for the big Gatwick Airport station revamp.

The increase spend knocked last year’s most used contractor Carillion into second place although spending with the firm only slipped 2.5%.

Together the two contractors now capture almost 10% of total spending by Network Rail on its improvements programme.

Amalgamated Construction joined the other big risers with its invoiced revenue rising from £159m to £210m over the year.

This year has also seen Morgan Sindall become one of Network Rail’s top 20 suppliers, after it was paid £89m for work on the rail network.

BAM Nuttall was the biggest slider this year as spending dropped by around £100m to £149m pushing it below J Murphy and Sons, which continued its steady rise up through the supplier rankings.

The Top 20 suppliers shared out £3.44bn, up from £3.1bn previously, which accounted for 47% of Network Rail’s total spend over the year.