Hopes of new safety measures being introduced on the Orwell Bridge before the end of year have been thrown into doubt by suggestions that work could be delayed until as late as April.

Despite highways bosses previously declaring confidence in completing work before 2015, it now seems the deadline has been extended until the end of the financial year.

Following a discussion with the Highways Agency (HA), Suffolk’s police and crime commissioner revealed that drivers may also be required to drive slower than originally indicated.

The HA announced plans last November to introduce a new speed limit in a bid to reduce accidents and ensuing gridlock, and that average speed cameras were likely to enforce the limit between the Nacton and Wherstead junctions.

There were also likely to be changes to slip roads at Shell service station on the westbound carriageway – identified as a factor in a number of “shunts” on the bridge.

Full details were announced at the end of January, when it was revealed that a new 60mph limit, enforced by average speed cameras, would be introduced this summer.

Work was delayed in July, when a Highways Agency spokeswoman said: “We are confident that we will be able to complete the changes by the end of the year.”

This week, Mr Passmore spoke to regional director Catherine Brookes, who told him improvements would be implemented by the end of the financial year at the latest, and that the HA was working to produce justification for a 50mph limit.

Mr Passmore said that cameras will be installed as soon as possible but that pending planning consents and consultations had been complicated by the presence of an Area of Outstanding Natural Beauty (AONB).

In the meantime he will discuss how the constabulary can help enforce the limit before the cameras are installed.

Mr Passmore welcomed a lower speed limit on the bridge and confirmation that improvements would be implemented. He said: “We know that any hold up on the A14 has a huge impact on Suffolk’s economy so I really welcome this constructive input from the HA,” he said.

“Implementing speed limit changes does take time so we will have to wait until the new year, the important thing is that we know the process is in place to get the work done.

“The lower speed limit should reduce the severity of any accidents that do occur and also reduce the numbers of accidents in the first place, which is very positive news.”

Ipswich MP Ben Gummer said that lasting plans needed to be put in place to ensure the prevention of costly traffic jams across all parts of Ipswich. He said: “Each time there is a serious accident on the bridge it takes hundreds of thousands of pounds out of the local economy.

“There is a long-term need to think more seriously about traffic in Ipswich – about upgrading the bridge and alternative routes around town. Rather than react when circumstances dictate, we need to be masters of our own destiny.”