Engineering work on train lines around Ipswich railway station could add to traffic delays on Sunday as thousands turn up for the first ever Great East Run.

The event, which follows in the footsteps of the hugely popular Great North Run, will have around 3,000 runners taking part, and thousands more on the streets cheering them on as they take on the half marathon.

A series of rolling road closures will take place from Saturday evening to Sunday afternoon and signs have already gone up warning motorists the routes to avoid on the day of the event.

However, concerns have been raised that the combination of road closures and train replacement services could cause gridlock in the town.

Network Rail are carrying out maintenance work between Colchester and Stowmarket and between Ipswich and Woodbridge on the day of the run which is set to close all the connecting railway lines.

Greater Anglia has had to replace train services with buses between Colchester and Stowmarket and between Ipswich and Woodbridge as a result.

A spokeswoman for Network Rail said it would be costly to the taxpayer to cancel the planned engineering works.

She said: “Our work is typically booked in 18 months in advance and we try to avoid clashes with big events.

“In this instance, our work was planned before the Great East Run was announced in January.

“Cancelling our work at short notice would be costly for the taxpayer and prevent us from carrying out improvements.”

A Greater Anglia spokeswoman advised customers to allow extra time for their journeys on Sunday.

She said: “Engineering works are often negotiated up to a year in advance.

“Factors such as special events are taken into account.

“Everyone will be able to complete their journeys on Sunday, however customers are advised to allow extra time.

“Buses will be diverted as necessary and customers will also be able to use their tickets to travel on First Ipswich’s 77 service.”

Stewards and course staff are set to assist traffic and pedestrians on the day of the event, allowing access to properties when it is safe to do so.

A spokeswoman for the Great Run Company said: “The provisional route for the Simplyhealth Great East Run was announced in January and we have communicated with our runners throughout this time over email, social media and through the Great Run website.

“Full road closure information is available on the website and information about the rail engineering works was included in the runners’ guide which was sent to all runners three weeks ago.

“As with all events, we ask participants to arrive with plenty of time to spare before the event and to plan their journeys accordingly.

“Our event village opens at 8am and there will be plenty for our runners and spectators to see and do before the starting pistol fires.

“The road closures and diversions put in place for a short time on Sunday will still allow access to much of the city centre, including Ipswich train station.

“Those who are planning to travel on the day should plan ahead and visit both the Great Run and Greater Anglia websites to avoid any potential disappointment.

“With any events of size and scale, there will be unavoidable disruption, but we hope that the majority of people see the event as an overwhelmingly positive one for Ipswich and Suffolk as a whole.”