Brussels: European Council President Donald Tusk on Friday said the European Union as a bloc is determined to stay unified after Britain voted to leave in a historic referendum on Thursday. Britons voted 51.9 per cent for Brexit against 48.1 per cent of 'Remain' vote in a historic referendum on Thursday. Britain joined the European Union on January 1 in 1973. "Today (Friday), on behalf of the 27 leaders I can say that we are determined to keep our unity," Xinhua news agency quoted Tusk as saying in Brussels. Tusk admitted that the EU had expected a different outcome of the referendum. "I am fully aware of how serious, or even dramatic, this moment is politically," he said, adding the historic moment is not a moment for "hysterical reactions". "There's no way of predicting all the political consequences of this event, especially for the UK," he said. The president said the EU has prepared for this negative scenario, though EU leaders were saying for weeks before the referendum that there is no "plan B" for Brexit. "As you know the EU is not only a fair-weather project," he said. He reassured that there would be no legal vacuum during the withdrawal process of the UK from the EU. "Until the UK formally leaves the EU, EU law will continue to apply to and within the UK," Tusk said, referring to both rights and obligations. The political decisions at the EU level will be taken at an EU summit scheduled for Tuesday and Wednesday, where leaders from EU member states and institutions will set the direction for what has to be done. In order to discuss the details of further proceedings, Tusk said he has offered the leaders an informal meeting of the 27 in the margins of the summit. "And I will also propose to the leaders that we start a wider reflection on the future of our Union," he added.