"We would be very foolish to assume everything would work from day one - there are bound to be some teething problems," said a spokesman for TfL.
The spokesman admitted there had been some problems with the phone signal via which data is transmitted from the self-service payment kiosk. However, he said, repair "hit squads" had been sent out to sort out any problems.
He also admitted there had been delays in processing motorists' applications but said this was down "to the sheer amount of applications rather than any problems with the IT" and that "extra people had been brought in to deal with it".
The spokesman insisted there was no connection between the hold-ups in processing the congestion charging registrations with last year's delays in vetting teachers by the Criminal Records Bureau. Both systems are run by IT services company Capita.
"This is a very different system," he said. "Then there was much more vetting than processing. I think there was a lot of politics going on behind the scenes with the CRB system - if you remember, the education minister resigned shortly after."
Although the back-end systems appeared to run smoothly yesterday, the congestion charge website suffered a number of performance issues as soon as the charge came into force, according to network monitoring firm Parallel.
The www.cclondon.com site suffered downtime and severely reduced performance during rush hour on 17 February when commuters jammed the system at the last minute, Parallel said.
The company monitored the website during the critical period from 12.00am on 16 February to 12.00am on 18 February. Key findings include:
The congestion charge site was available for 98.92% of the time over the test period
The performance changed dramatically around 8am yesterday increasing download times by approximately three times
At the same time it was also recorded that there were several download timeouts - this is where the page and its contents could not be downloaded within 45 seconds. This indicates that the server, or its internet connection may have been overloaded between 9am and 11am
- The transaction test (which tested the first two steps to paying the congestion charge online) also showed the same pattern of performance problems, with the payment transaction doubling from 14 to about 28 seconds yesterday after 8am