LU had hoped to start work this month on the 4.2 ha site, which is owned by Railtrack, but now believes it will have to obtain listed building consent to demolish railway arches supporting the viaduct.
LU project manager Alan Thornton said he had been warned that an application to Tower Hamlets council for consent could take 18 months. He said: "There will certainly be weeks or a few months of delay."
But Thornton said it was still possible for the extension to be ready on time. He said: "We are re-examining the programme. Jobs that are earmarked to run consecutively can be run concurrently instead."
We are re-examining the programme. Jobs that are earmarked to run consecutively can be run concurrently instead
Alan Thornton, LU project manager
LU is holding a series of meetings with planners to decide how to proceed with the project. It has given tenancy extensions to businesses on the site while it holds these meetings.
Businesses had been ordered to leave the goods yard by the middle of this month to allow for demolition, but have now been granted permission to stay until 9 April. Will Bailey, the owner of three businesses in the goods yard, has called for a judicial review of his eviction claiming that there is no guarantee that the extension will go ahead.