Parliament (Privileges, Immunities and Powers) Act 1962 s 6

s 6 Exemption from liability in certain cases

6.—(1) No Member shall be liable to any civil or criminal proceedings, arrest, imprisonment or damages by reason of any matter or thing which he may have brought before Parliament or a committee by petition, bill, resolution, motion, or otherwise or may have said in Parliament or in committee. (2) No person shall be liable to any civil or criminal proceedings, arrest, imprisonment or damages by reason of any act done under the authority of Parliament or the Speaker and within its or his legal powers or under any warrant issued by virtue of those powers.