It has been a clear own goal. Over the past decade, Scotland has had a steady decline in its precious stock of sporting facilities in the face of mounting pressure from property developers.

Official figures show the number of sports pitches has fallen steadily since 1996 despite attempts to halt the decline, fuelling fears for the future health and fitness of the nation.

Since 1996, the total number of pitches lost is 118 while at the same time there has been a sharp rise in the number of planning applications proposing the loss of pitches - from an average of 60 a year between 2000 and 2003 to the current annual rate of more than 160.

Although these figures include all pitches, not just those serving schools, the loss has been partly blamed for the fact that Scottish pupils take part in less physical education than nearly any other country in the developed world.

Meanwhile, fewer than one-third of Scotland's local authorities have drawn up strategies to stop the decade-long decline despite being urged to do so by sportscotland, the national sports development agency.

It is against this worrying backdrop that sportscotland today publishes new guidance aimed at protecting school playing fields across Scotland.

The document, entitled School Playing Fields - Planning and Design Guidance, sets out for the first time the recommended number of outdoor pitches primary and secondary schools of different sizes need to deliver the PE curriculum.

The guidance was prompted by the high level of current and planned projects to modernise school buildings, particularly through the use of Public Private Partnership (PPP) projects.

Sportscotland also realised there was little up-to-date advice on school playing fields and that the requirements of financing projects, advances in synthetic grass pitch technology and changes to the way school PE and sport are delivered all have implications for choosing appropriate provision.

To this end, the guidance provides a model for calculating playing field requirements for a range of school sizes as well as technical guidance on playing field dimensions, layout, design and maintenance. However, those who have watched with mounting concern at the growing disappearance of pitches, while welcoming the new step, are concerned the guidance may not have enough "teeth" to make a real difference.

Chris Robison, policy director for the Scottish Sports Association, an umbrella organisation for governing bodies of sport in Scotland, said there was a frustration because the guidance was at the discretion of local authorities.

"My understanding is that it is very good advice and is widely held with high esteem, but where the problem lies is that it is not compulsory. If (councils) want to ignore it, they can."

Fiona Hyslop, education spokeswoman for the SNP, welcomed the guidance, but said it was "too little too late" given the number of playing fields already lost. "In order for this guidance to be taken seriously and to make a difference it needs to be mandatory," she said.

James Douglas Hamilton, education spokesman for the Scottish Tories, added: "Our playing fields should be seen as precious assets that we should be looking to nurture, not destroy."

However, Charles Gray, education spokesman for Cosla, which represents local authorities, insisted councils were doing all they could to improve sports facilities for schools under difficult circumstances.

"Planning departments are under increasing pressure from developers and have to take difficult decisions because of tight budgets, but in most cases facilities are getting better," he said.

While council officials accept it is beneficial to have a model which sets out the ideal playing fields, they argue that it is for them as education managers - held to account by locally elected members - to decide whether or not their facilities are adequate to deliver the PE curriculum.

"Sportscotland is advocating that councils buy a Rolls Royce when in reality what they need and can afford is a Ford Focus," said one local authority education official.

The perspective of local authorities is backed up by the planning regulations which allow sportscotland to object formally to any proposal which would lead to a loss of sporting facilities.

There is a frustration from councils that in many cases PPP initiatives are delivering benefits to pupils because they improve on what has been offered before, but still might fall short of sportscotland's "ideal" and are therefore open to criticism.

Mr Gray added: "As a matter of course, local authorities which have PPP schemes liaise with sportscotland to make sure that facilities improve.

"The reality is that it costs many thousands of pounds to modernise a pitch and some local authorities don't always have the financial clout to go the extra mile, but are still committed to improving what is on offer. We have to live in the real world."