Glasgow Science Centre has been urged by an MSP to "come clean" about the closure of its giant rotating tower.
The 416ft (127m) structure, which sits on the banks of the Clyde, is Scotland's highest free-standing tower.
Glasgow MSP Sandra White has asked why it has again been closed to visitors during the busiest part of the year.
A spokesman for the science centre admitted that because of "significant technical issues" it was unlikely to open for the rest of the year.
The tower, built 10 years ago at a cost of £9m, is not connected to its foundations, allowing it to rotate 360 degrees from the ground up.
The whole structure rests on a small base bearing, which has caused problems for years.
It is estimated that the tower has only been open for 25% of the time since it was built.
The MSP believes the science centre management ought to be more open about the situation, given the public funding which went into the project.
Sandra White said: "I am calling for an inquiry into the whole situation with the Science Centre Tower.
"This isn't the first time the tower has been closed but this particular time no reason has been given.
"I will be writing to government ministers, Scottish Enterprise and the leader of Glasgow City Council to instigate an inquiry into this situation."
The science centre is an independent charity which aims to promote science, education and innovation.
A spokesman said: "The tower operated on occasions last year, but it became apparent that there were significant technical issues, primarily to do with the bearing on which it stands.
"We have discussed these with the contractors and relevant engineers and are working with them towards a solution.
"The time frame is such that it is unlikely we will operate the tower this year, as we don't want to try to operate something unreliable."