ADVOCATES have pledged to protect a green space next to the Lye Valley nature reserve in Oxford after development plans were given the go-ahead.

Friends of Lye Valley secretary Heather Armitage said residents were “bitterly disappointed” after city councillors approved plans to build 10 homes on the patch of grassland east of Warren Crescent.

She added councillors have pledged to “call in” the application, allowing planning officials to review the proposals and give the group more time to voice their concerns.

Ms Armitage said it was vital to protect the land, known by residents as Warren Meadow, as it was a rainwater catchment area for springs which go down to the 8,000-year-old Lye Valley Fen.

She added: “Developing could be detrimental for this very rare habitat that is so precious but we don’t know because it would be an experiment.

“It’s so fragile and a lot of people care about it. It’s part of our history and heritage.”

Turley Associates first submitted plans to develop 10 three-bed homes near the nature reserve in June 2013 but then submitted amended plans in September.

Oxford City Council’s East area planning committee approved the proposals earlier this month, which include car parking, cycle and bin storage and creation of a public footpath.

Developers said they worked with Natural England to create a drainage system that would limit the impact on spring water feeding into the Lye Valley nature reserve.

But Ms Armitage said residents were not convinced there was enough evidence proving the sustainable draining systems would protect the fen.

The 4.5 hectare site, which dates back to the Ice Age, boasts 20 species of plants on the county’s rare plants registers and relies on rainwater which trickles down from the grassland. More than 750 people have signed the Friends of Lye Valley’s petition calling on the city council to designate the land as local green space, which would protect it.

Volunteers have also spent more than 1,500 hours tending the area since plans were submitted.

Ms Armitage added: “There is an awful lot of effort and time and devotion going into this site. Is it worth risking for 10 houses ?”

In his report to the committee, planning officer Andrew Murdoch said: “The proposal for the homes would make an efficient use of this site that has been allocated for residential use as part of the council’s five-year housing supply to provide good-quality and affordable housing while at the same time establishing a balanced and mixed community within the Headington neighbourhood area.”