A millionaire businessman today won permission to launch a High Court challenge over the Government's refusal to hold a referendum on the EU Reform Treaty (the Lisbon Treaty).
Stuart Wheeler, a major Conservative Party donor, claims that he had "a legitimate expectation" that Gordon Brown would hold a vote.
The Government's decision to "resile from their promise" should be declared unlawful, he said.
Mr Justice Owen, sitting at London's High Court, ruled today that Mr Wheeler, 73 - who made more than £30 million from spread-betting firm IG Index - had "an arguable case" that should go to a full hearing.
He has raised £150,000 from 150 donors to pay for his High Court battle.
Mr Wheeler said after gambling thousands of pounds on his bid to obtain permission, and then winning his day in court: "The Government's lawyers tried to get the case thrown out, maintaining on various grounds that my case was unarguable.
"I am delighted that the judge has decisively rejected that.
"The moral case for a referendum was overwhelming. The legal case is strong, based upon a series of promises to the electorate.
"The legal premise of the case is that it is in the interests of good administration that the Government should implement their promises, unless there is a sound reason not to.
"No reason has been given."
The full hearing is expected to take place at the High Court in London on 9-10 June.
Responding to the ruling, a Foreign Office spokesman said: "This decision simply means that there will be a hearing - it does not affect the outcome of the case.
"The threshold for what constitutes an arguable case at the permission stage of judicial review is low.
"Hardline Eurosceptics brought similar cases in respect of earlier European treaties, so this case is no surprise. Those challenges all failed.
"We are confident of the strength of our case on this occasion and look forward to putting our arguments before the court in more detail in due course."
Rabinder Singh QC, applying on behalf of Mr Wheeler for permission to seek judicial review, said the application was based "on the underlying fundamental principles of good administration, fair play and straight dealing with the public".
The Government had given an "unequivocal and repeated" promise to consult the British people on whether the UK should ratify the Constitutional Treaty - the substance of which was replicated in the Lisbon Treaty.
He asked: "What's in a name when the substance is the same?"
Philip Sales QC, appearing for the Office of the Prime Minister, said Mr Wheeler's case was "not properly arguable".
He said Mr Brown and Foreign Secretary David Miliband denied that any unambiguous and unqualified representation had been made amounting to a promise that a referendum would be held.
Mr Sales also argued that Mr Wheeler's claim was "misconceived" because the ratification of an international treaty was not a matter open to challenge in the High Court, and such a challenge would breach parliamentary privilege.
The judge rejected all of Mr Sales's submissions in a significant victory for Mr Wheeler.
He said: "In my judgment it is arguable that the claim, couched in the narrow terms that it is, does not amount to a violation of parliamentary privilege for the reasons advanced by Mr Rabinder Singh."
Mr Singh had submitted that the promise made in relation to the Constitutional Treaty extended "by implication to any document with a different name having equivalent effect".
The judge ruled: "He (Mr Singh) submits that the court will be concerned with substance not form, and that if, as he asserts, it be the case that there is no material difference between the treaties, then the obligation to hold the promised referendum cannot be avoided simply by the fact that it now bears a different name.
"In my judgment this point is arguable.
"Thus the claimant seeks to advance an arguable case, and it follows that there will be permission to apply for judicial review."
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