CITY councillors were warned they may come to regret voting to approve the expansion of Seacourt Park and Ride.

Campaigners who fought the plans for the past year cried 'shame' and 'resign' as the Planning Review Committee narrowly approved the plans at Oxford Town Hall, and opponents warned the Secretary of State – who now has to make a final decision – may yet throw the whole scheme out.

Oxford City Council put forward the plans to expand the park and ride to cope with extra demand caused by the Westgate.

It was approved last month but had to be looked at again after number of councillors called it in.

As with the original West Area Planning Committee, tonight's decision once again balanced on a knife edge until the final minute, with four councillors coming out in favour and three against out of the committee of nine.

The scales were tipped in the final seconds by councillor David Henwood who made a snap decision to vote with John Tanner, Nigel Chapman, James Fry and Chewe Munkonge.

Councillor Mary Clarkson, who sided with Ruthi Brandt and Andrew Gant in voting against (with Pat Kennedy abstaining), said after the vote that approving the 685-space expansion onto a green field was 'short-termism', putting officers' plans above the long-term risk to the green belt and flooding.

Arguing it tested government planning rules, she said the decision tonight could prove costly to the council when the Local Government minister Sajid Javid looks at all the evidence.

She said: "I think officers could have made the point this has to now go to the Secretary of State, and perhaps some councillors would have voted differently."

John Tanner, proposing the motion in favour, said he believed the expansion would reduce flood risk at the site, and argued that whether in 10 years or 20, Oxford would need more parking spaces and it was best to act sooner rather than later.

Julia Hammett of Oxfordshire Badger Group, who helped get more than 1,500 signatures on a petition against the plans, was among a number of protesters who attended the meeting.

After the meeting, she warned: "I think Oxford City Council will have to look back on this as not their proudest moment.

"I believe the Secretary of State will say 'no', and when the next elections come around we will see what happens [to these councillors]."

The two-and-a-half hour debate threw up plenty of contentious issues, including the revelation that the Environment Agency has never monitored groundwater flooding on the site – only river flooding – and a table apparently showing rising usage at Seacourt which was then revealed only to show data for Tuesdays, Wednesdays and Thursdays.

It is not known when a final government decision will be made.