A private company which maintains part of the Tube network, has failed to meet targets for cutting delays.
Tube Lines has been fined £10m
Tube Lines, which looks after Jubilee, Northern and Piccadilly lines, blames events like the Camden Town derailment and Green Park signal failures.
But it says delays were down by 30% in 2003, with further improvements expected this year.
Tube Lines will be fined several million pounds by Transport for London, although the exact figure is unknown.
Tube Lines hit its target for "lost customer hours" - the amount of time travellers waste because of delays or train failures - on only two, four-week periods.
Passengers on the Jubilee Line wasted 300,000 hours more than the target
On the Northern Line it was 180,000 hours
On the Piccadilly Line it was 140,000 hours
But the company says it has done better than required on providing clean and graffiti-free trains and on improvements to stations, such as ensuring the dot-matrix board indicators operate properly.
Tube Lines is responsible for about a third of the network's maintenance, under the 30-year Public Private Partnerships contracts.
The other lines are run by Metronet, which began work last April.
According to Transport for London, Tube Lines will have been paid almost £500m by the end of next month.
Metronet will have received £750m.
Tube Lines' Terry Morgan said: "We are asking Londoners to be patient.
"We have many programmes of improvement and some are delivering.
"But it is when the major investments come into play, that we will see a sustainable improvement to the Underground."