A standing stone marks the site (picture from David Rankin)

The protest, which began about 1500 BST, was organised by Stirling historian Stuart Wilson.

He said: "We oppose the university's plan to build the pitches on what is without a shadow of doubt, Scotland's most significant battleground.

"The site is certainly as important as Bannockburn or Culloden.

"The battlefield and the stone which marks it are our heritage.

"What is happening is appalling and would not be tolerated in any other country.

'Contravene planning guidelines'

"By having a peaceful protest, we hope that Stirling University will see the depth of feeling for this site and reconsider."

The university's proposals also include plans for a golf practice area, changing pavilion, roads and car parking.

The university wants to develop sports facilities

Historic Scotland said that its own clear recommendation that the pitches be situated elsewhere on campus had been ignored.

Archaeologist Deirdre Cameron said: "The plans contravene national planning and policy guidelines and basically would have an adverse effect on an important historical setting.

"The site is still not too different from what the countryside would have been like when the standing stone was erected. "

A spokesman for Stirling University said: "Most people didn't even know the stone was there until we announced our plans for the rugby pitches.

"We have planning permission and we are complying with that."