After a downgrade from ratings agency Standard and Poor's last evening, Greece now has the worst rating of any sovereign in the world. Athens' debt was downgraded by three more notches, a sign that the agency thinks it will be forced to downgrade Athens to default - or D - as private creditors are likely to be involved in the country's next bail-out. S&P said that in its view Greece is increasingly likely to restructure its debt in a manner that would result in one or more defaults. Its ten year bonds have jumped to trade at 17.2% this morning. Portuguese and Irish 10-year bond yields are also trading at euro-era highs of 10.63% and 11.48% respectively this morning. Reacting to the downgrade, Greece accused the rating agency of shutting its eyes to reform efforts in Athens and EU talks on new debt aid. 'This decision overlooks actions by the government to preclude any problems in Greece's contractual obligations,' the Greek finance ministry said, a reference to fears that Athens will be unable to repay its crushing debts. The downgrade to CCC also ignores ongoing talks between European Union officials for a 'sustainable solution' to finance Greece's payment needs, the ministry said. The latest blow came as European finance ministers prepared to meet today to discuss a new aid package for Greece that could call on private holders of Greek debt to contribute by accepting delayed payment.