To ask the Chairman of Committees what is the condition of the building structure of the Palace of Westminster.

My Lords, as your Lordships would expect with a building as old and heavily used as the Palace of Westminster, there are some very significant maintenance issues which require considerable investment. The Parliamentary Estates Directorate is in the process of formulating a 25-year strategy to address these challenges. The most pressing problem is that the mechanical and electrical systems are in a poor state of repair, which is why we have embarked on a five-year programme of "aggressive maintenance" to mitigate the most serious equipment failures. At the same time, investigative studies are taking place to scope the longer-term programme of works.

My Lords, I thank the noble Lord for that reply. Is he aware that on the odd occasion when I have seen him in conversation with worried-looking officials, it has normally been about the state of the building? As we spend an awful lot of time here, can he tell us what is the state of the walls, the foundations and, in particular, the roof?

My Lords, the walls and foundations are in reasonably good condition. If I look worried, it is largely because of the mechanical and electrical programme which I mentioned in my Answer; that is a serious programme. As for the roofs, noble Lords will be aware that the first phase of replacement of the cast iron roofs has taken place down at Speaker's Court end, and the scaffolding is now being removed. That is the first phase. We need to take stock of the results of that work before we move to the next phase, which will be the south return-down that end of the building. Unfortunately, the results of the work on the first phase have been more difficult than we had anticipated. We had anticipated that about 10 per cent of the roof tiles would be good; as it turns out, in some places, nearly half have had to be replaced.

My Lords, although what the noble Lord has described is no doubt essential, can he give us an indication of what it is all going to cost?

My Lords, I can give the House an indication of the cost of the first phase of this program for M&E, which is budgeted at £69 million to go to 2015. After that, it is anybody's guess.

Turning to a different aspect of the building, can the noble Lord tell us what is happening about the cellars, because they have historically-especially 400 years ago-been the source of trouble? Perhaps there may be some special interest there.

My Lords, I hope that the cellars will no longer be a source of trouble. Of course, it was not this building where that happened, it was its predecessor. The cellars are now crammed full of old pipes, wiring and, in particular, asbestos, of which there is a lot. All that is having to be dealt with.

Will the noble Lord please comment on the heating system in the House?

My Lords, first, I am well aware that there have been problems with the heating in various parts of the building. I hope that your Lordships will agree that it is better today than it was last week-particularly in the Chamber. It is a major problem with an old building such as this that a lot of the hot air that we produce in this House leaks out through doors, and so on, being left open. We are conducting serious work on this. We have someone looking around the place to see where the main causes of trouble are.

My Lords, can the noble Lord confirm that the roofs of the Chamber and the Royal Gallery were replaced about 10 years ago? I recall a committee on which I was sitting going up and being shown the new or refurbished tiles. They haven't gone wrong again, have they?

Certainly as far as the Chamber is concerned, the ceiling was replaced some years ago when one of the things fell down. I was in the Chamber when it happened and we had to move into the Royal Gallery for a shortish period. As for the roofs, I am not aware that the actual roof tiles were changed at that time.

My Lords, can the Chairman of Committees give some comfort to our admirable curator's department which, because of the many valuable pictures in the Palace, is on a constant state of alert for water coming into the building? The water usually comes in at this time of year, normally as a result of bad repairs to the original structure, which was obviously of a much higher standard than the repairs.

I am aware that there have been problems particularly above the Royal Gallery, where the gutters, which are extremely difficult to get at to keep clean, have sometimes caused water to come in and go down the walls of the Royal Gallery and possibly damage the paintings there. It is something that we keep constantly under attention. We also employ birds of prey to deal with the other birds which make a mess.

My Lords, can the Chairman of Committees tell the House what will be the impact of the two Houses sitting during September on the necessary programme of works, given that the House authorities have historically been able to count on a long period to get some of these essential works done? In particular, can he say whether this is likely to have a detrimental effect on the costs?

My Lords, a September sitting does incur additional works expenditure because of the need to accelerate or delay individual projects. The extra costs involved will, of course, vary each summer depending on the proposed schedule of works. Last summer, we estimated that a September sitting in the House of Lords would have added approximately £1.3 million to the cost of shared and Lords-only projects. Those concerned were made aware of those figures.

In the light of the need for an uninterrupted run of work, particularly on engineering and electrical works, is it not unfortunate that the House has been called to sit in September 2011, which will of course interrupt that essential work?

My Lords, I rather think I just answered that very question for the noble Baroness. I do not think that I have any more to add to what I have just said.