David Cameron's plans to set out his vision for Britain's future in Europe in a major speech have been thrown into disarray after he was forced to cancel because of the Algerian hostage crisis.
In a dramatic development, Mr Cameron postponed his visit to the Netherlands to make the long-awaited speech and hold talks with Dutch opposite number Mark Rutte.
The speech, which has been several months in the planning, has brought debate at Westminster over the UK's future membership of the EU to fever pitch.
Mr Cameron had been due to make his speech on Friday morning, and was expected to fly to the Netherlands on Thursday night.
After it became clear that several Britons had been caught up in the hostage incident, arrangements were made for him to chair a meeting of the Government's Cobra emergency committee by video-link from The Hague if necessary.
But as news came through of violent clashes and multiple deaths at the desert gas plant, the decision was taken to postpone the speech to a date and venue yet to be confirmed.
Mr Cameron sought to prepare the ground for his speech by calling his opposite numbers in Germany, Sweden and the Netherlands earlier in the week. And on Thursday he discussed what he was planning to say on European policy in telephone calls with US president Barack Obama and French president Francois Hollande.
Tory factions, coalition ministers and business leaders all heaped on pressure in advance of what was billed by former British ambassador to the US, Sir Christopher Meyer, as the most important speech on Europe by a British PM since 1945.
Labour leader Ed Miliband warned that Mr Cameron was about to take Britain "to the edge of an economic cliff" by creating uncertainty for business, while Vince Cable warned him not to take a "dangerous gamble" with the national interest.
The White House made clear that Mr Obama maintained the pressure on the Prime Minister in the call. A spokesman said: "The President underscored our close alliance with the United Kingdom and said that the United States values a strong UK in a strong European Union, which makes critical contributions to peace, prosperity, and security in Europe and around the world."