Tube maintenance consortium Tube Lines has boosted pre-tax profit by 24% to £73.1m in the year ended 31 December 2007.

Figures for 2006 cover the last nine months of the year, when pre-tax profit was £45.2m.

Comparable turnover at the company, in which Amey and Bechtel are the two shareholders, rose from £852m to £855m. Its profit margin increased from 6.9% to 8.5%.

Terry Morgan, chief executive of Tube Lines, said: “It’s been another challenging but satisfying year for Tube Lines. Once again I can report that we have completed our major projects on schedule and continue to make progress on the upgrade programme for the Jubilee and Northern lines.” The company is also responsible for work on the Piccadilly line.

David Begg, the chairman of Tube Lines, said Metronet’s collapse into administration last July would not affect his business because it had the “right people with good skill sets and motivation” to make the PPP system work.

But he warned that the decision to press ahead with the £16bn Crossrail project should not risk the maintainance of the tube network.

He said: “We need to make sure the decision is not made at the expense of investment in the existing tube infrastructure. We simply won’t get the world-class underground system London needs if we rob Peter to pay Paul.”