If France's rejection of the European Union's constitutional treaty was a body blow for pro-EU campaigners, last week's Dutch rejection - a whopping 63 per cent vote against - must be considered a knockout.
Even before last Wednesday's drubbing, the UK's leading pro-EU lobby group, Britain in Europe (BiE), had accepted that a UK vote on the constitution, pencilled in for next year, was looking unlikely.
BiE campaign director Lucy Powell said in a statement on 30 May that 'without a campaign to fight, Britain in Europe would have to review its future'.
The group's destiny will be decided by its 20-strong advisory board, which includes former Labour Party leader and EU commissioner Neil Kinnock, ex-Conservative government minister Lord Brittan (also an ex-EU commissioner) and Finsbury co-founder Roland Rudd. Powell said a decision could be taken as early as this week.
BiE's partner, the European Movement (EM), also has to consider whether it still has a purpose. EM's membership and campaigns officer Jonathan Church says the movement, set up in 1948 by Winston Churchill, will decide upon its next step at its AGM in Nottingham on 18 June.
Rocky path to recognition
Since BiE was launched in 1999 by political heavyweights Tony Blair, Gordon Brown, Kenneth Clarke, Michael Heseltine and Charles Kennedy - under the stewardship of then campaign director Simon Buckby - the road has been a rocky one.
The group has seen various noteworthy comings and goings of the political world's well-known communicators. Adrian McMenamin, the Labour Party's outgoing chief general election press officer, held the post of head of campaign information for BiE between 2002 and 2003.
Stephen Noon, a former press secretary to the Catholic Archbishop of Westminster who now works for SNP leader Alex Salmond, left his post as BiE chief press officer after just seven months last November.
Noon had replaced Danny Alexander, who was elected the Liberal Democrat MP for Inverness in last month's general election. Alexander, one of the few former BiE campaigners who will talk openly about his role at the group, says he decided to go after the Government made it clear there would be no early referendum on whether the UK should adopt the euro.
'The pro-Europeans have to learn from this experience,' he says of the Dutch and French referenda. 'There is a fundamental question to be answered about improving their communication of what is happening at a European and member state level. It is very important that they explain what the EU really is, what it does and why it does it. But they also have to listen to what people have to say about the EU.'
Both Alexander and Buckby - who left BiE in 2003 and is now a partner at Luther Pendragon - lay the blame for BiE's failure to make the case squarely at the door of the Government and pro-European British political establishment. Their refusal to get their hands dirty, Buckby argues, doomed BiE to failure.
'There is no impulse in the British political establishment to back the pro-Europe campaign,' he says. 'If that support is not there, how can it succeed?'
It is telling that Buckby, Alexander and Richard Watts (who had worked at BiE for four years, latterly as head of the political unit) all decided to quit BiE at the same time for the same reasons. The Chancellor's decision to kick the euro debate into the long grass meant the very thing BiE had been campaigning for was not going to happen.
Now a significantly diminished BiE finds itself in the same position.
Sharing a building and a press office with the EM, BiE says it has just two staff in London and another two outside the capital, compared with around 30 head office staff and nearly 20 regional staff at the height of the euro campaign two years ago.
BiE has not been able to call on any rich donors, while anti-EU groups have been lavishly funded, and Powell points out that it would have been 'irresponsible for us to take on more staff and spend money we would need for the campaign itself'.
Powell is supported by BiE chief press officer Ben Jones, who replaced Noon this April. 'Even if BiE's future is unclear, we would hope that there will be some organisation that will take up the EU baton,' says Jones .
But it is difficult to see how BiE or anyone else's efforts to explain the positive impact of the EU on bread and butter issues like jobs and clean air can ever have a significant effect in such a hostile media environment.
As Watts recalls, BiE has had its work cut out to get positive EU stories on the inside pages of even sympathetic newspapers such as The Independent.
On the other hand, negative tidbits picked up by Eurosceptic writers such as The Sun's Trevor Kavanagh are often splashed on the paper's front page.
As Alasdair Murray, an ex-Times journalist and deputy director of the Centre for European Reform (a pro-EU think-tank independent of BiE) puts it: 'Journalists on Eurosceptic papers want to find any details that reflect badly on the body of the EU. To counter that takes more than a few under-funded lobbying groups and think-tanks.'
TIMELINE: UK PRO-EUROPE MOVEMENT
1997: As opposition leader, Tony Blair follows John Major in committing to hold a referendum on adoption of the euro.
1999: Prime Minister Blair, Gordon Brown, Ken Clarke, Michael Heseltine and Charles Kennedy launch Britain in Europe.
2000: Treasury sets out 'five tests' for adoption of the euro.
2003: Brown rules out early referendum on the euro. BiE campaign director Simon Buckby, head of campaign information Adrian McMenamin, head of comms Danny Alexander and head of political unit Richard Watts quit. Lucy Powell takes over from Buckby.
2004: Blair confirms Britain will have a referendum on the EU constitution . BiE hires Stephen Noon, the Catholic Archbishop of Westminster's press secretary, to replace Alexander.
2005: EU founding members, The Netherlands and France, reject EU constitutional treaty, UK pro-European groups prepare to retrench.