Virgin Media have been hit with over £8,000 in fines for offences which include carrying out unsafe working practices.
The charges were imposed after Transport for London (TfL) accused them of causing a danger to road users and breaching permit conditions.
The Government agency also claimed the utility firm created unnecessary delays and disruption.
On April 30 Virgin Media were hit with a £5,000 fine at Westminster Magistrates' Court.
The company pleaded guilty to five offences committed in Croydon Road in October last year.
They faced one charge of carrying out unsafe working practices and two charges for breaching permit conditions.
The final two charges were for failing to serve the necessary statutory notices.
Virgin Media were accused of unsafe working practices for not providing any guarding around an open hole.
There was a primary school nearby, prompting District Judge Goldspring to point out the potential seriousness of the blunder.
Leon Daniels, Managing Director of Surface Transport at TfL, said: "We expect that utility companies ensure that any disruption caused by roadworks is minimised and the most stringent safety is upheld.
"We are pleased the court has agreed the unnecessary delays caused by utility companies’ slapdash behaviour are thoroughly intolerable.
"We are completely focused on cutting delays and will be continuing to prosecute persistent offenders who show wanton disregard for Londoners, as we have Virgin Media."
Virgin Media had to pay the maximum victim surcharge of £420 as well as covering TfL’s legal costs.