Contractors could be facing a financial penalty after roadworks caused rush hour delays on a busy Ipswich road.

Temporary traffic lights were left in place in Norwich Road for an extra day after work was carried out by tRIIO on behalf of gas firm Cadent over the weekend.

Partial road closures on adjoining Springfield Lane and Lower Dales View Road, had also been left in place, although these had not contributed to the congestion.

The lights were still in place on Monday morning, resulting in delays of more than 30 minutes.

Suffolk Highways, which maintains the majority of the county's road network, took the lights down in time for the evening to clear the key route, which links junction 53 of the A14 with Ipswich town centre.

Cadent has apologised and pledged to investigate what went wrong, but Suffolk Highways has warned it could impose a penalty for the delays.

A spokeswoman for Suffolk Highways said: "Suffolk County Council has permitted tRIIO gas services, working on behalf of Cadent to work across three weekends to complete gas main connections.

"These works have been coordinated to avoid clashes with ITFC home games.

"Network Assurance were made aware of the temporary traffic signals in place this morning along Norwich Road, as well as partial road closures along Springfield Lane and Lower Dales View Road.

"An inspector was sent to inspect the site and the contractor was instructed to remove the unauthorised traffic management and clear the site.

"To support the traffic signals, and to enable a safe area for operatives and road users, two road closures were in place on Springfield Lane and Lower Dales View Road, whilst the works are ongoing.

"Where utility services overrun their permitted time on site, and in this case causing disruption on the network, the contractor will be issued with a financial penalty."

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A spokesman for Cadent said the work has been completed in two weekends rather than the three it was originally planned for.

"Work was carefully planned and agreed with the local authority to ensure it was delivered with minimal disruption," the spokesman added.

"To reduce inconvenience to road users we agreed with the local authority to carry out this work over three weekends when roads are generally quieter - though the work has been completed in just two weekends.

"As part of this work subcontractors were tasked with providing temporary traffic lights, to enable the work to be carried out safely and effectively. The traffic management subcontractors had been instructed to remove these upon completion of the weekend's work.

"Unfortunately, this was not done as instructed, and we are investigating the circumstances as to why this was, to ensure it does not happen again.

"We do all we can to ensure work delivered by ourselves and our contractors and subcontractors, causes minimal inconvenience to the public, and we're sorry for any disruption that has occurred as a result of our work."

The works were part of an essential gas mains replacement to connect properties to the gas network in Norwich Road.