MP are our representative / agent & us the principal how can agent go aheah make decision without consent?

I mean it in legal terms of principal and agent. I know they have the vote or authority to represent us but does that mean they can act on our behalf even when we not at all agree with them ? and in the case of loss shouldnt Law of tort applies ? Please answer in detail .

This has already been processed through the court. Once elected, the MP is a free agent. You are not a principle anymore than a minor stockholder is a principle in a decision of the Board of directors.

No. We vote them into power and as a group decide that they are the best person for use to have as our Representative. As MP they sign a contract. Tort law is the name given to a body of law that creates, and provides remedies for, civil wrongs that do not arise out of contractual duties (Wikipedia). This nullifies your point and proves that you do not understand the Tort law. Tort law is compensation of losses due to negligence, nuisance, defamation, intentional, economic or competition torts. Statutory Tort would be the closest to this situation. This is when the Legislature imposes duties on public or private parties such as the Product Liability Directive, which gives manufacturers the responsibility of defective products causing harm.