Bit of advice if possible? I'm a tradesman and have been employed to install two bathrooms in a domestic property. The owner is having a lot of other building work done, including two knock throughs and other structural work. The other builder responsible for these works is a mutual friend, however as the job was dragging on the client asked me to price for board and plastering the downstairs as he has paid the other guy up to date,and just wants it finished. I agreed to take on the plastering if he was positive he wanted to use someone else, and would get it done while he is on holiday. However now I have cleared the site and had a proper look at the structural work, it's apparent that what I knew was maybe a bit shoddy is actually shocking, and dangerous. No building control insolvent,and another builder I showed it to has condemned it,and is willing to put it in writing that the property is unsafe and the work dangerous. I've cleared the site and shut down the job, but am now in an awkward situation where I have to inform the client, whilst on holiday that work has stopped, and worse still his pal has basically ruined his house,and will potentially have to remove everything he's paid for and start again... I'm not going to inform building control, but I'm also not going any further or rectifying any of the other guys work. I'm going to inform the client of my concerns, but wondered if I am duty-bound to report dangerous work to building control or face liability if he doesn't rectify it?