on 16 December 2004 to start accession negotiations with Turkey from 3 October 2005. While Austria and Germany initially wanted to leave open the possibility that negotiations with Turkey would lead to a privileged partnership, less than full membership, accession negotiations were ultimately launched with the "shared objective" of membership. Turkey's accession talks have since been stalled by a number of domestic and external problems. Both Austria and France have said they would hold a referendum on Turkey's accession. In the case of France, a change in its Constitution was made to impose such a referendum, but later another constitutional change has enabled the parliament (if a large majority of its members agrees) to prevent such a referendum. The issue of Cyprus continues to be a major obstacle to negotiations. European officials have commented on the slowdown in Turkish reforms which, combined with the Cyprus problem, led the EU's Enlargement Commissioner Olli Rehn in March 2007 to warn of an impending 'train crash' in the negotiations. Due to these setbacks, negotiations again came to a halt in December 2006, with the EU freezing talks in 8 of the 35 key areas under negotiation. In 2007, Turkey stated that they were aiming to comply with EU law by 2013, but Brussels refused to back that as a deadline for membership. In 2006 European Commission President José Manuel Barroso said that the accession process will take at least until 2021. In a visit to Germany on 31 October 2012, Turkish Prime Minister R.T. Erdoğan made clear that Turkey was expecting membership in the Union to be realised by 2023, the 100th Anniversary of the Turkish Republic, implying that they could end membership negotiations if the talks had not yielded a positive result by then. Turkish President Abdullah Gül said that upon completing the accession process Turkey will hold a referendum for Turkish membership in the European Union. In December 2009, the Republic of Cyprus blocked 6 chapters of Turkish accession negotiations, including those on Judiciary and Fundamental Rights, Energy and Education and Culture, arguing that Turkey needs to first normalise relations with Cyprus. As a result, no chapters have been opened since June 2010. Hence, there is no chapter Turkey can open other than the difficult and economically detrimental chapters Competition Policy, Social Policy and Employment, and Public Procurement that most candidate countries open at the end of accession as all other