The iconic home of Big Ben will not reopen until the second quarter of next year with the final bill expected to now be just shy of £89m.
Sir Robert McAlpine is main contractor on the job which was originally costed at £29m.
Parliament released the latest update on Monday on the project.
This summer will see work start on installing the restored clock mechanism and scaffolding will be removed from the Tower from the Autumn.
Early in 2022, the bells – including Big Ben itself – will be reconnected to the original Victorian clock mechanism and will ring out across Westminster once again.
The gantry, which has protected the Palace of Westminster throughout the works and supported the complex scaffolding structure, will be removed before the site is fully cleared prior to the Summer of 2022.
A revised business case was approved in early 2020 and “the project has stuck rigidly to the revised budget of £79.7m.”
The additional costs of £9m. now incurred “relate solely to the impact of Covid-19”.