I have not gone into research on that matter, but, prima facie, the copyright of the speech is the Member's. Then the speech may be reproduced by someone else. Another person may have intervened in the reproduction and again that reproduction may be tinkered with or improved. In each case there may be an additional copyright.
In that case I am not going to give advice. As the hon. and learned Member for Hornchurch has said that it is very dangerous for Law Officers to give an opinion in certain matters, I think I will follow his advice here as well.