Parliament's restoration slips two years before MPs vote, and each year of delay could add £420 million

The hold-up is on the Northern Estate, the buildings where MPs are supposed to sit while the palace is emptied. Heritage approvals, too little space for site setup and budget pressure are slowing that refurbishment, according to the committee's report released Nov. 4. The Lords' planned move to the QEII Centre has its own problem, because the deal to buy the building is still not done.

A vote by MPs and peers is due before 2026 is out, covering a £3 billion first phase and a shortlist of two restoration options. Moving both Houses out entirely is priced at £11.1 billion to £15.6 billion over 19 to 24 years. The phased alternative, with smaller moves, comes to £19.5 billion to £39.2 billion over 38 to 61 years. The final route will be picked in 2030. A debate pushed beyond late 2026 would run into lapsing procurement frameworks and cost a further nine to 12 months, Construction Enquirer reported.

Inside the first phase, riverside security, relocating building services and work on the medieval cloister court still have no price. An unallocated £500 million pot has to pay for them and also serve as contingency. The committee wants one combined plan covering the restoration and the temporary homes, firm numbers for the unpriced packages, a look at competitive dialogue so contractors can weigh in, and simpler governance. Committee chair Sir Geoffrey Clifton-Brown put the price of each postponement in the hundreds of millions of pounds of taxpayers' money. Until there is a decision, the weekly upkeep bill for the old building is forecast to climb to £2 million, up from £1.5 million.