Health and Safety Executive
As from April 2015 all works will be notifiable to the Health and Safety Executive.
In terms of responsibility it is not only the contractor who is responsible for health and safety, but also the professional advisors, architects and consulting engineers, but more importantly the client or home owner.
The responsibilities borne by each of the parties to a contract are onerous. The client or home owner has a responsibility under Health and Safety to appoint a demonstrably competent contractor, preferably one with their own engineering staff who are professionally qualified to ensure disasters like that reported above do not occur.
The Top Makeover is Below Ground - 'The Times' - Article on Basement Conversions
An interesting article by Carol Lewis on basement conversions - published in The Times 'Bricks & Mortar' section.