The grand old Gothic lady by the Thames, now 160, is cracking, crumbling and leaking. The oldest existing part of the world heritage site, Westminster Hall, dates back 1000 years.
Officials admit the problems of restoring Britain's most important and ornate public building have been put off for far too long and now "the nettle has to be grasped". But it could land the taxpayer with a bill well over £1billion.
Some preliminary work has been done, but in the next fortnight the firm of experts tasked to carry out an extensive survey will be announced.
Creating a new parliament has been firmly ruled out, but three basic options face the Westminster authorities and the parliamentarians:
l Carry on with the piecemeal repair ad infinitum.
l Have a defined rolling programme of restoration, working around the work of parliament.
l Or move out the MPs, peers, officials and staff to a nearby venue and spend several years refurbishing the Palace in one go.
Officials admit that, because such a mammoth overhaul has never been undertaken since the Palace was rebuilt following the great fire of 1834, they do not know how long a full restoration would take. However, it is likely to be at least one parliamentary term ie five years.
Usually, any restoration work is agreed and overseen by officials in the Commons and the Lords but, given the scale of the work ahead, MPs and peers will become involved with a joint committee and there will be votes on what should be done. This could prove difficult as, unlike with legislation, where the Commons takes precedent, each House will have an equal say.
Richard Ware, programme director for restoration and renewal, accepted there might be problems ahead but noted: "They will be condemned to agree."
He stressed the programme of renewal would be as transparent as possible but accepted bureaucratic processes might hinder a smooth progress. He even acknowledged that a Yes vote in next year's independence referendum could add a further obstacle as it might lead to more changes in UK Governments. "We are well aware of this," said Dr Ware.
The scale of the task ahead is truly enormous.
While some sections of the leaking roof have had their iron tiles replaced, the majority still need to be restored. The ornate roof-top decorations, including the many gargoyles, have been badly eroded.
At ground level, cracks in the limestone walls appear everywhere due to the weather and badly installed post-Victorian toilets. The Palace was clearly not designed for modern use.
Below the chambers is a stuffy, subterranean world, containing miles of pipes and cables along long stretches of corridors. Access for workmen is a nightmare.
In an age when politics is derided and politicians derided even more, the biggest task facing the Westminster authorities in their restoration attempt could be convincing the UK taxpayer that such a massive scale of work and the gargantuan repair bill attached to it is necessary.
But one official insisted: "This is the greatest historical building in Britain. We have to preserve this for the nation not just for today but for future generations."