Scotland also signed seven new agreements to develop floating offshore wind projects that would supply renewable energy to help North Sea oil and gas operations replace gas and diesel power and reduce carbon emissions.
Cost projections have run between $8 billion and $16 billion for the project to renovate the 1,100-room Victorian-era complex by the River Thames in London.
The estimated $5-billion restoration of the 19-century landmark was approved in 2018, but the organization responsible for overseeing work was begun only in April.
With the deadline temporarily delayed for the U.K.'s exit from the European Union and a crucial vote due this week, the construction industry is waiting for clearer signals on what will happen next.