Campaigners against the Go Ape adventure course in Pollok Park are claiming a victory after Glasgow City Council admitted it has "no record" of how it designed the public consultation exercise which has formed the basis of its argument for the development.

Responding to a freedom of information request, the council said it had no record of the authors or the methodology of the consultation, which many park-goers claim was poorly advertised and Nicola Sturgeon, the Deputy First Minister, described as "woefully inadequate".

Meanwhile, it emerged yesterday that the park has suffered a spate of vandalism, with anti-Go Ape graffiti slogans being sprayed on signs and notice boards.

There have been more than 800 official objections to Go Ape's proposed treetop assault course in the North Woods, many from park-goers who say the council did not do enough to advertise the proposal, which is set to be decided by the planning committee in the next month.

The public were invited to respond through an open-ended pro forma questionnaire on the council's website. But only 237 people did so, half of whom were schoolchildren who were given forms as part of an exercise. In all, 199 were in favour and 38 against - a majority which allowed the council to go to the planning stage.

Andrew Johnson, a member of Save Pollok Park, said: "It is quite clear that this consultation, from a research perspective, does not pass muster.

"One is bound to wonder why the request and pro forma was not sent to the 350 individuals and agencies the council already had on its circulation lists.

Bill Fraser, chairman of Pollokshields Community Council and a member of Save Pollok Park, said: "We have always argued that this consultation was flawed. Now we have the proof - the council cannot explain how it was founded."

The campaigners also used the FOI legislation to request copies of the council's correspondence and minuted meetings with Go Ape since January 2007, but were told this would require a fee of £129.49.

A council spokeswoman said: "Our efforts to consult with the public and interested organisations went beyond our statutory requirements.

"For example, we held a public event in September in the Burrell Collection auditorium which was widely publicised through a poster campaign in all local community facilities and supermarkets within an approximate two- mile radius of the park."