The developer of a major tourist attraction has missed its target to secure crucial financial backing for the project.
Last year Brighton and Hove City Council agreed to loan almost £15 million to kick-start the i360 scheme.
Plans for the £38 million, 183-metre viewing tower near the West Pier were first unveiled six years ago.
The council-backed loan to developer Marks Barfield was due to be signed off by Tuesday ahead of the authority’s Policy and Resources Committee meeting next Thursday, but the final details of the agreement have yet to be hammered out.
Marks Barfield said discussions were ongoing.
Director David Marks said: “There was a target date but we are still in discussion. It’s very complicated.
“We have been very careful not to set an absolute deadline because that would give the perception that we have missed something.
“We are in the process of reaching agreement. I very much hope construction will start this quarter but I am reluctant to give a date.
“There are a lot of partners in the deal and a lot of documents which have to be signed at the same time. There’s a lot of work to be done.”
Council leader Jason Kitcat said: “It was a working target, but financial close is always complex and it is not unusual for it to slip as lawyers and accountants get involved.
“There has always been an element of flexibility over the dates due to the number of stakeholders and complexity of the project.
“We are committed to working with Marks Barfield to get work started on site, with the aim of the i360 opening in spring 2015.”
Meanwhile Brighton businessman John Regan said he has formed a consortium to help develop the West Pier in partnership with the i360.
Mr Regan said he has drawn up detailed plans which he will discuss with Marks Barfield.
He said: "A new West Pier has the ability to become one of the principal expressions of the city’s vision, transmitting the authentic values of beauty, quality, confidence and integrity.”