Teesside Park has been given the green light to double the size of some of its units.
Owners British Land submitted a document to Middlesbrough Council's planning department in November, notifying them of potential changes to buildings at the Leisure Park side of the complex.
It wasn't a request for planning permission - but instead, British Land was looking for a Certificate of Lawfulness of Proposed Use or Development.
A covering letter and a host of drawings which accompanied the document spelled out that a number of units, including the Showcase Cinema and Hollywood Bowl, could have mezzanine floors added - although there is no suggestion that there is any plan to do so.
The correspondence argued that although planning permission is usually needed for building and development work, as the mezzanine floors would only effect the building's interior no further planning consent would be necessary.
And Middlesbrough Council has now agreed.
British Land had said the original planning permission for the leisure park, granted in 1989, and all the updated planning permission documents granted since, did not prohibit new floors being created in any of the buildings at the Leisure Park.
The document read: " Teesside Leisure Park has seen little investment since it was developed in the early 1990s. Currently, the significant proportion of Block C [which includes the Millennium and the former casino] is vacant.
"British Land Leisure Ltd are exploring the potential to undertake a comprehensive refurbishment or redevelopment of the property. To input into the assessment of potential options, British Land Leisure Ltd are seeking to confirm with the council the existing lawful position and the potential for the inclusion of additional floorspace at mezzanine level within the individual units."
The current Burger King, Pizza Hut and Imperial City food outlets would see its available floor space doubled under the proposals, as would Hollywood Bowl.
The Showcase Cinema could see its available space creep up only slightly, from 6,417 sq m to 7,244 sq m.
The former Gala Bingo and Casino units could see the amount of indoor space increase.
But proposals would see the former Millennium nightclub actually get smaller, if the proposals turn into reality.
British Land did not respond to requests for comment from Teesside Live.
