Railway engineers are "urgently" redesigning Warwick station's multi-million-pound accessibility upgrades after Victorian foundations were unearthed.

Network Rail was midway through work to install new lift shafts down into the station's subway to provide step-free access to both platforms for the first time.

However, workers have found foundations believed to be from the first railway station built on the site in 1852 - which lasted just 42 years before being destroyed by fire in 1894.

Network Rail said the foundations were not recorded in the plans of what was then rebuilt 129 years ago.

The near 200-year-old walls now lie right where the lifts were due to go, and the substructure cannot be disturbed as it is "integral to the existing building and platform".

It means new detailed designs now have to be drawn up for the lift shafts, pausing the building work for the time being.

The unexpected foundations found after demolition of concrete subway steps at Warwick station (image via Network Rail)

Because construction inside the subway is well underway, it will stay closed with the diversions staying in place.

People are being urged to use this route correctly, with incidents of people trespassing across the tracks to get between platforms still causing safety concerns.

Network Rail has apologised to passengers and local people for the unexpected delay.

Elinor Weymouth, scheme project manager for Network Rail, said: "We know how much the accessibility upgrades mean to people in Warwick and we're sorry this unexpected setback means the building work has to be paused.

"We are committed to delivering this vital work so the station is accessible for everyone, and are working hard to get new plans drawn up and workers back on site as soon as we possibly can.

"I want to thank passengers for their patience while this work goes on behind the scenes and urge everyone to continue to follow the walking diversion that's in place while the subway is closed."

The brick foundations going far deeper than on any known Warwick station plans (image via Network Rail)

Despite the pause to work, security and platform patrollers will be at the station to prevent people trespassing on the tracks and guide passengers to the correct diversionary route between platforms.

Platform 1 has been temporarily shortened during the work so it can take place safely while allowing trains to keep running.

This means one less train a day calling at Warwick - though those services continue to call at Warwick Parkway and Leamington Spa.