Thousands of commuters faced massive delays after over-running railway repairs stopped trains between Oxford and Didcot.

Buses were laid on for some passengers struggling to get to London - only for one of the replacement vehicles to break down on an A34 sliproad minutes after leaving Oxford train station.

The 50 passengers then had to walk back from the Botley interchange to the station to get taxis.

Steve Martin, whose journey to London Paddington started at Charlbury, at 6.10am, said: "The coach broke down just after turning on to the A34 slip road, with water pouring out of the back of the coach.

"We were then told to make our own way back to Oxford station. We trudged back along the slip road and grass verge - this makes me think of an Ealing comedy but somehow I am not smiling.

"I then managed to get into a taxi at Oxford station, after catching a bus to the station and finally got into Paddington at 8.42."

First Great Western is asking the stranded coach passengers to contact it to claim compensation.

Engineering work at Hinksey over the weekend over-ran. Trains should have been able to run between Oxford and Didcot Parkway but services were cancelled until 8.07am. Even then there were still delays until lunchtime.

Clive Pearce, who runs Berinsfield-based Pearces coaches, added: "I sympathise with the passengers because they have had a double let-down. They chose to walk back to Oxford instead of waiting for another bus and were not in any danger."

A spokesman for Network Rail said: "Equipment failure meant we were unable to complete important engineering works to schedule.

"A full investigation into this incident will take place over the coming days."

Lance Cole, a spokesman for First Great Western, said 13 trains were "trapped" in Oxford, leading to delays throughout the morning.

Graham Thomas, a train crew manager who tried to help passengers, said: "We got about seven 50-seat buses to come and take passengers to Didcot.

"Plenty of staff were on hand to help passengers out and give them advice."

Mr Cole added: "Thousands of passengers were affected and it is extremely disappointing.

"First Great Western was affected by two Network Rail engineering over-runs which impacted our customers' morning commute - principally across the Oxford and Thames Valley routes.

"We apologise for the delays, which were beyond our control. Our staff worked hard to minimise the delays and knock-on effects for passengers on the Cotswold, Thames Valley and local lines.

"The problems were unforeseen and we are confident that the Network Rail investigation will yield valuable lessons."