Scotland's largest city has effectively withdrawn from the investment collaboration of the Scottish Cities Alliance, withholding its own plans from the group's £6 billion joint prospectus for growth.

In a clear breach of the pan-Scotland spirit behind the SCA, a spokesman for Glasgow City Council told the Sunday Herald it had decided not to contribute to a seven-city blueprint of investor-ready projects compiled by Aberdeen, Dundee, Edinburgh, Inverness and Stirling. The council said the decision was based on it being already ahead of the other cities.

Glasgow's statement implies that the Commonwealth Games host sees no benefit in aligning with other Scottish cities to achieve extra visibility in the eyes of overseas investors.

A spokesman for Glasgow council said: "Glasgow has already started work on our infrastructure development plans with our partner authorities along the Clyde Valley, and we are ahead of the other cities in this regard. We are in dialogue with both the UK Government and the Scottish Government about these plans."

The £7 million Scottish Cities Alliance was launched in 2011 by infrastructure minister and Glasgow Govan MSP Nicola Sturgeon to "build on the strengths and opportunities that exist within the cities and their regions to attract investment, create jobs and support Scotland's cities to compete internationally".

Development experts at the time told the Sunday Herald its success in pooling resources would depend on the appointment of a strong-willed, effective and well-connected project leader, capable of "knocking heads together" to end inter-city rivalries.

As suggested by the failure of the axed £600,000 Glasgow-Edinburgh Collaboration Initiative (2006-10), the cities at either end of the M8 have a history of unproductive competition for investment cash. The fact that their projects will not appear in the same portfolio for investors will be seen as a setback for the project.

The SCA, administered by the public-private Scottish Council for Development and Industry and now led by Stirling Council deputy chief executive Stewart Carruth, has so far resulted in better strategic understanding of the city's assets and strengths and closer relationships between civic leaderships, but little in the way of tangible economic benefits.