Tube users will be surprised by the improvements made to London Underground services over the next few years, says a manager of one of the new consortia running the network.

Stephen Peat, director of operations for Tube Lines, the consortium responsible for the Piccadilly, Northern, and Jubilee lines, said plans to improve cleanliness, safety, and reliability on these lines would be highly successful.

“I think we will have some sparkling results in the next few years,” he said.

Mr Peat today outlined Tube Lines’ program for improving these lines, amounting to £4.4 billion of spending over the next seven years.

Tube Lines, since it assumed responsibility for the three lines at the start of this year, had already made clear gains in keeping trains cleaner and graffiti-free, he said.

There had been a 12-fold increase in the cleanliness of trains, and the average number of graffiti tags on trains had fallen from 60 to 10, he said.

Amongst the £500 million of contracts Tube Lines has already awarded are £160 to add a seventh car to Jubilee line trains, improving capacity by 17 per cent, and £200 million to replace or refurbish 155km of track- almost half of the track on all three lines.

Signalling remains a priority in terms of further improvements, but Tube Lines have not yet finalized details for this.

Jim Haines, projects director, said a £500 million contract to replace signaling on all three lines should be placed toward the end of this year.

Regular users of the Northern line, which suffers from signalling problems, would not be surprised by Mr Haines saying the line had a "complex signalling system".

Signals on the Jubilee line will be replaced by 2009, the Northern line by 2011, and those on the Piccadilly by 2014.

“If you have a safe signaling system, it allows you to run more trains closer together and faster,” he said.

The other lines on the Tube network are now being run by the Metronet consortium.