MPs have voted to move out of their historic home at the Palace of Westminster so essential restoration work can be carried out.
The vote on Wednesday could see them relocate to temporary accommodation for at least six years, although not until the middle of the next decade.
Peers will vote next week on whether to support to the plan.
If they do it could finally bring to an end years of wrangling as to how the work on the crumbling 19th century edifice should be carried out.
In 2014 a consortium headed by the accountancy firm Deloitte was appointed to examine the various options.
MPs could relocate to Richmond House during the ‘decant’ (Kirsty Wigglesworth/PA)
The following year, it came back with a series of three scenarios as to how it could work.
The first option was for a rolling programme of works to be carried out over an estimated 32-year period with MPs and peers remaining in the building while the work was carried out around them.
At an estimated cost of £5.7 billion it was the most expensive of the three proposals.
The second was for a “partial decant” with first one House, either Commons or Lords, and then the other moving out to temporary accommodation while the restoration was carried out.
Lords could have a temporary home at the Queen Elizabeth II Centre during the restoration (David Mirzoeff/PA)
The work was expected to take 11 years at a cost of between £3.9 billion and £4.4 billion.
The final option was the “full decant” with both Houses moving out. The cost was put at between £3.5 billion and £3.9 billion with the work expected to take six years.
In 2016 a joint committee of MPs and peers backed the full decant proposal, with the Commons moving to the Department of Health building at Richmond House and the Lords to the nearby Queen Elizabeth II conference centre.
Alternative proposals, such as moving Parliament to a series of temporary rafts moored in the Thames or relocating outside of London were rejected as impractical.