Europe's Human Rights watchdog hit back today in the continuing war of words with London over voting rights for prisoners.
Prime Minister David Cameron is defying a Strasbourg court ruling that the UK's blanket ban on all prisoners voting while in jail is a breach of human rights.
But a draft Bill before Parliament - announced as a deadline expired for action to change the law - includes the option of keeping domestic rules unchanged.
Now the Council of Europe's Committee of Ministers, which monitors whether countries are implementing Human Rights Court judgments, has issued a reminder that the status quo will not do.
The move is bound to reinforce rumblings over whether the UK should leave the Council of Europe's 47-nation club - nothing to do with the EU - if sovereign control over human rights is ceded to Strasbourg.
The Committee of Ministers - effectively the ambassadors of the 47 member states of the Council of Europe - used its latest quarterly meeting to pass judgment on the Government's decision to set up a joint committee of both Houses to look at the issue.
On the agenda are three options - changing the rules to allow those sentenced to less than four years to vote; changing the rules to allow only those serving six months or less to vote; and maintaining a blanket ban on prisoner voting.
The odds are that a majority of MPs would choose the third option - triggering today's new warning from Strasbourg: "The third option aimed at retaining the blanket restriction criticised by the European Court cannot be considered compatible with the European Convention on Human Rights," said the Committee of Ministers.
But no showdown seems imminent: the Committee said it would look at the case again "at the latest" in September next year.
Meanwhile, the Committee said it noted "with great interest" that the UK authorities had introduced legislative proposals to Parliament on November 22 with a range of options for amending domestic electoral law on prisoner voting.
It said it strongly supported Lord Chancellor and Justice Secretary Chris Grayling's statement to Parliament that "the Government is under an international legal obligation to implement the (European) Court's judgment" and "the accepted practice is that the UK observes its international obligations".
The Committee considered that "the final version of the legislation that will be proposed to Parliament should be in conformity with the fundamental principles recalled in this announcement".
In effect the Committee has challenged the UK to choose one of the other two options - although it does not suggest what sanctions could be imposed if MPs ultimately voted to keep the blanket ban.
When announcing the three options being considered, Mr Grayling told MPs that Parliament was "sovereign" and had the power to defy the European Court of Human Rights. And even if Strasbourg tried to impose fines, he said, MPs could choose not to pay them.
But he said the Government had an "obligation" under international law to bring forward proposals to obey the ruling.
The Commons has previously voted overwhelmingly to maintain the ban.
Council of Europe Secretary General Thorbjorn Jagland - in Norway today awarding the Nobel Peace Prize to the EU - said he felt the Human Rights judges had left the UK with enough of a "margin of interpretation" to be able to choose how many prisoners will be allowed to vote.
He said: "I'm concerned that the domestic debate against more political integration in the European Union is confused with the broader aim of human rights.
"The UK has been a leader in human rights and I urge it to continue in this tradition."
The Ministry of Justice insisted tonight that MPs should have the final say.
A Ministry spokesperson said: "The strength of feeling in the UK on prisoner voting is clear. And we have been clear in our view that it should be for national Parliaments to decide."