Network Rail has announced that because of problems found during the refurbishment of the Botley Road bridge in Oxford, Botley Road underneath the ridge will remain closed until October next year.

The original plan was for Botley Road to open next month, with a further six-month closure from March 2024. Although engineers are now working round-the-clock work, the delays encountered now mean that Botley Road must remain closed until October 2024.

Last June, work on the £161m Oxford station and railway upgrade was suspended when contractors unearthed an inverted brick arch, thought to be part of the original Victorian drainage system. Ground investigations have shown that the arch is far larger than envisaged, being one metre deep and stretching for about 100 metres between Mill Street and Frideswide Square, and is thought to be part of the structural support for the bridge.

Because of the size of the arch, the project had to be redesigned to ensure the bridge remains stable and fully supported while the utilities under the road are diverted. This has required the installation of 700 piles and a temporary drainage system to manage groundwater until the installation of a new permanent pumping system.

Further disruption work came in July when a WWII-era hand grenade was found within the work site requiring the evacuation of the nearby area.

Three piling rigs started drilling last month and will continue until mid-October, but because they are so noisy, they will only be in operation between 8 am and 6 pm on weekdays and on alternate weekends. To reduce disruption to residents and businesses, quieter work will take place outside of these hours.

The bridge refurbishment is in connection with a multi-million-pound project to upgrade Oxford and its surrounding road network to improve journeys and provide better rail connections east of Oxford. These are part of the Oxfordshire Connect programme, and when complete Oxford station will be a bigger and better and able to accommodate more passenger and freight services.

Improvements to the road network around the station include safer junctions with Botley Road and the provision of a four-metre cycle and footway on each side of the main road to provide more space for cyclists and pedestrians.

Further information about the project is available at www.networkrail.co.uk/oxfordshireconnect the latest highways information is at www.oxfordshire.gov.uk/oxfordstation, and mail updates can be obtained via https://lineside.networkrail.co.uk/oxfordshireconnect.

Dale Crutcher, Network Rail’s industry programme director for Greater Oxford, said: “This project is extremely complex and has been made even more challenging by the extent of the brick arch underneath the road. We’ve explored a number of options to deliver the works which included moving to working around the clock, but unfortunately, with needing the infrastructure to be ready by the end of next year we have no choice but to keep the road closed until October 2024.

“I understand this will be disappointing for residents and businesses, and I’m sorry for the disruption this will cause.

“Engagement with stakeholders will continue with the next local community drop-in at West Oxford Community Centre on Wednesday 27 September between 2.30 pm and 6.00 pm, where members of the project team will be available to answer your questions.”

Councillor Andrew Gant, Oxfordshire County Council’s Cabinet Member for Highways Management said: “Obviously it is disappointing that Botley Road will remain closed for longer than expected but there was no alternative due to the difficulties faced by Network Rail in this complex project.

“We continue to thank residents, commuters and businesses who have been affected by this work for their patience and understanding. As the highway authority, we will continue to work with Network Rail and other partners and discharge our duty to manage the highways network effectively.”