 The Palace of Westminster is home to one of the busiest parliamentary institutions in the world. Thousands of people work here and visit every day. And millions of tourists are drawn to its iconic splendour. Completed in the mid-1800s, many of the palace's features have never undergone major renovation. So what's being done to tackle any problems? Not only to ensure the palace continues to function as a working building, but also to preserve its unique heritage for future generations. In this video, we will look at the mechanical and electrical systems of the palace. These provide essential services, such as heating, water, ventilation and power. Essentially the arteries of the building, they're critical to the continuous operation of parliament. Shafts and tunnels, originally designed for ventilation, have become the roots for hundreds of miles of cabling for telephones and computer systems, as well as steam heating pipes and conditioned air. These roots are now extremely congested, making it difficult to access, maintain or repair the services. Of all the elements of the building, it's the mechanical and electrical services that have the shortest and the most predictable lifespan. And their obsolescence can only be dealt with effectively by replacement. Some of the pipe work in these tunnels is between 60 and 100 years old, way beyond their predicted lifespan. There's a high risk of breakdown, making the current approach of replacing systems only at highest risk of failure, unsustainable and more costly. In 2012 alone, almost 3,000 electrical faults needed repairing. There are 98 MND risers and 128 plant rooms. This was deemed to be a very high-risk plant room that was failed imminently, so we stripped out all of the plant, we're now removing all of the asbestos and indeed the paint as well. There is asbestos within the Palace of Westminster, you'd expect that of a building of this age, especially since there was a reconstruction after the Second World War and there's a lot of asbestos as insulation material around the building services. It is well managed, we have an excellent management plan assisted by the use of consultants. We have specialist contractors in the tent up an area, they put it under negative pressure and they remove the asbestos from the floors, from the voids, from the ceiling, from all around the services. There are two layers to this room, the two layers have taken three months, so it's quite a substantial cost and impact the programme of the works, but it's the right thing to do. The plant room originally had four air-handling units, the rent crossways, very, very tight, very, very congested, as are many of the other plant rooms within the Palace. They've now been removed and we're replacing with two, far more efficient, about 80% more efficient than the original. One of the key constraints is that we must have no impact to the building users or indeed any other visitors. So we've developed this temporary plant room to enable us to actually strip out the Law's plant room that we've just seen. It's very, very costly, very, very time consuming, but during the process we've had minimal impact on the users of the building. We've got 128 plant rooms within the Palace of Westminster. 80% of those are in the basement and the remaining 20 are at ground level and in the roof voids. We have a strategic phase programme of refurbishment works to the plant rooms and infrastructure within the Palace, but this by no means takes away the problem. Or it is an interim phase to reduce the risk of failure. Now some of this pipe work is 110 years old and it's still functioning. The main heat source is steam and the steam boilers are right at the end of that corridor. Because the infrastructure is so old that has given us tremendous problems with leakage. When the heating system starts, usually in September, we do get an awful lot of leaks and an awful lot of manpower is used to solve those leaks. We're in plant room B. Part of the work package is to remove the specialist cables from the plant room. The plant room has steam on aged infrastructure pipe work. Should the pipe work fracture, then it would take out all these specialist systems. Specialist systems include low voltage power, building management system, fire, detection system, communications and data. We've undertaken significant surveys around all of the Palace of Westminster and we've worked out what needs to be done. We've prioritised that list and we're currently going through a phase programme of replacement of infrastructure where we can. Bearing in mind the building is fully occupied. Recently a pipe burst in the floor above the committee corridor and discharged 30,000 litres of water in 15 minutes. It found its way down through the building structure and flooded the corridor below. It took three weeks to repair and at the same time, essential live services running through the corridor floor had to be managed. Repairing the aging mechanical and electrical systems couldn't be put off any longer because the risk of system failure is so high. But this medium term programme of work is just a fraction of what needs to be done. Only 15% of the highest risk building service plant rooms are being replaced to buy time while a longer term approach is identified. To find out more, please watch the other videos in this series.