Leaked sponsorship brochures suggests corporate backers will be able to link their brands to everything from new pathways and seating in the gardens to a 5000-capacity amphitheatre to replace the Ross Bandstand.
The Quaich Project has pledged that big-money backers will be given access to a “international high-net-worth networks” of other supporters, including at VIP-only concerts. Alan Cumming and KT Tunstall launched a worldwide fundraising campaign in New York last year. Further events are already being planned in London and Los Angeles.
The Quaich Project, a public-private partnership set up by the city council and the Ross Development Trust to pursue the gardens revamp, has launched a £25 million appeal even though the overhaul does not have planning permission.
The sponsorship material could not be found on the city council or Quaich Project websites.
If given the green light by councillors, the project would see a Hobbit House-style replacement for the existing Ross Bandstand, a two-storey visitor centre and hospitality complex overlooking Edinburgh Castle and a permanent cafe near the Ross Fountain.
Senior figures at the trust say the proposed replacement of the “outdated and inflexible” facilities at the existing bandstand, which dates back to 1935, would “open up possibilities” for the expanded use of the park throughout the year.
However potential backers are being told that for the project to be successful it needs “the active support and financial investment from a wide array of partners: businesses, philanthropists, charitable grant-making bodies and all those with a vested interest in improving this vital green space in the heart of Edinburgh.”
Fundraisers say sponsors will also be able to organise corporate days out for staff and their families, set up “pop-up stations” in the gardens, get private tours for up to 25 employees and even a talk with the project architects.
Sponsors are being sought for “VIP overseas dinners” and “Victorian-themed” events in a former gardener’s cottage in return for being able to raise their “brand profile” at them.
The leaked material states: “With unparalleled marketing potential in both location and profile, The Quaich Project offers a unique opportunity to sponsor a portfolio of brand new, world-class facilities.
“From new pathways and seating areas to adventure play parks and a 5000-capacity concert venue, there are various elements available to showcase your brand and increase experiential marketing activity.
"The Quaich Project will create new ways to celebrate Edinburgh’s status as one of the world’s most innovative, welcoming and thriving capitals - generating new global connections and raising this landmark location’s profile on the world stage.
"Our vision is to reimagine this place as a ‘space for all’ - bringing together the latest thinking in architectural, landscape and environmental design to create a joyful space that celebrates modernity and history, virbancy and tranquility, practicality and artistry.
"Our sponsorship packages are tailored with your marketing, budget and business goals in mind.
"Each will be delivered by a dedicated account manager who will assist with monitoring and evaluation before, during and after the sponsorship’s activation."
Mike Small, spokesman for the Citizen campaign, set up last year to “defend” Edinburgh against the privatisation of public space, overtourism, gentrification and “festivalisation,” said: “These latest revelations are devastating and paint a picture of further privatisation of public space.
"This is common good land being turned into a debenture scheme by a private company the public has no control over.
“This is the shift of a public good into a private asset and will further accelerate the process by which the ordinary citizen will be excluded from their own city.
"This sell-off and sell-out should be stopped immediately.”
Terry Levinthal, director of the Cockburn Association heritage watchdog, said: “It comes as no surprise that these prospectuses are available and that a range of ‘products’ are being offered for sale.
“The gardens are a common goods asset, held for the benefit of the citizens of the city.
“They are not a corporate asset for sale and whilst philanthropic giving is to be welcomed and indeed supported, we need to be extremely cautious about any conditions of gift attached to such giving.
“No agreement with any individual donor must be allowed to erode the common good value of the gardens nor bind the city in such a way as to restrict civic aspirations for the gardens in the future.”
Conservative councillor Phil Doggart said: “The residents of the city have expressed concerns about how public spaces are managed and for whose benefit.
"The SNP-Labour administration must at least act as if it is in control of the management of the gardens, even if the citizens of Edinburgh know that it is rarely in control of anything.”
Jules Haston, director of development at the Quaich Project, said: "Edinburgh is a city built on philanthropy and it’s the far-sighted individuals and companies who we have to thank for many of the facilities that we enjoy today.
"A fundraising campaign to deliver a capital project of this scale requires a comprehensive supporter engagement programme to inspire and encourage financial contributions.
"So far, we’ve secured £5,639,996 from individuals, £272,650 from charitable trusts including Edinburgh World Heritage and £17,064 from corporate sponsors to put on small scale events. We’ve got a long way to go but right now we’re working to raise awareness about the project and taking the plans step by step through the processes of planning and public consultations.
"The people that we are looking to for monetary support are individuals, charitable trusts and foundations, businesses and the public sector. Support from corporate partners is divided into corporate social responsibility i.e. donations through corporate membership, and corporate sponsorship.
"With the latter the supporting businesses may require some brand profile or other recognition. However, all corporate sponsorship located in the gardens will be subject to approval from the city council."
A spokeswoman for the city council said: “The work of the trust to raise funds for the project is due to reported to us later this year. We look forward to receiving this update.”