There has to be 12 Justices of the Supreme Court. The 12 existing Law Lords were going to take over - Lord Scott was going to retire and be replaced by Lord Clarke. But Lord Clarke was succeeded as Master of the Rolls by Lord Neuberger leaving only 11 Justices. So who will be the 12th? It is currently predicted that Lord Justice Dyson will be appointed.
But will he get a peerage? Peerages cannot be given out under the Appellate Jurisdiction Act 1876 any more because the Constitutional Reform Act 2005 repealed it. He could be given a Life Peerage. Lord Clarke was given a life peerage in June 2009 before becoming a Justice of the Supreme Court in October 2009. Life Peerages are usually also given to the Lord Chief Justice if he is already not a peer (Lord Judge for example)
But the Government has said this:
All new judges appointed to the Supreme Court after its creation will not be members of the House of Lords; they will become Justices of the Supreme Court.
There was an idea that new Justices would not get a peerage but would be entitled to be called Lord and Lady as senior judges in Scotland are. But we have not heard anymore about this. So it looks more likely that the new Justice - will be Rt Hon SIr John Dyson, who will have to sit with his Baron and Baroness brother and sister judges as a mere Knight Bachelor.
It then looks likely that the Court will be stable for a while -until Lord Saville retires in 2 years time (although he has yet to sit in the Supreme Court - having only been an active Law Lord for 1 year before he was appointed to the Bloody Sunday Inquiry for 11 years - he is due to deliver his report and starting sitting in the Supreme Court this year).