"Following the recent development, a no-deal scenario is highly likely. Let there be no doubt that a no-deal scenario would be extremely costly and disruptive. The economic consequences would have a significant impact on the UK and, to a lesser extent, on the EU", he told reporters.
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The EU has been preparing for all scenarios for a long time, Katainen added, repeating assurances of the European Commission president, Jean-Claude Juncker, who said earlier there would be no short Brexit delay past the new deadline of 12 April.
UK lawmakers voted 313-312 on Wednesday to push for UK Prime Minister Theresa May to negotiate a new extension of Article 50 with Brussels in a bid to avoid a no-deal exit. But it is the European Union which will ultimately decide whether to grant an extension. An EU summit on the issue is expected to be held on 10 April.