I have read and re-read you post several times to make sure that I understand the situation.
Sorry, but you have no redress against the BCO - he has done nothing wrong and has not been negligent. He is also under no obligation to provide you with an opinion on what would happen without the beam being installed.
This might be a fraudulent act by the builder, but the inspector is under no duty to act as a 'building policeman' and chase these things up.
Building Control cannot be 100% on the ball - it doesn't act like that. If you take your car for an MoT, it may officially pass, but that doesn't mean it's 100% roadworthy. It's down to statistics, really. The Building Regulations regime just aims to prevent serious, life-threatening failures, which in this country it does. Beyond that, it's down to relations between builder and client.
I suspect that if you try and sue your BCO, you'll just get nothing except frustration.
Sorry, but you have no redress against the BCO - he has done nothing wrong and has not been negligent. He is also under no obligation to provide you with an opinion on what would happen without the beam being installed.
This might be a fraudulent act by the builder, but the inspector is under no duty to act as a 'building policeman' and chase these things up.
Building Control cannot be 100% on the ball - it doesn't act like that. If you take your car for an MoT, it may officially pass, but that doesn't mean it's 100% roadworthy. It's down to statistics, really. The Building Regulations regime just aims to prevent serious, life-threatening failures, which in this country it does. Beyond that, it's down to relations between builder and client.
I suspect that if you try and sue your BCO, you'll just get nothing except frustration.