"The PM's position is that it's new deal or no deal but no delay", said a senior British government official.
After the deal was announced, Johnson joined the EU's 27 other leaders at a summit in Brussels, shaking each by the hand as he entered the room and laughing and joking with German Chancellor Angela Merkel and French President Emmanuel Macron.
Brussel: Britain and the European Union said on Thursday that they have struck an outline Brexit deal after days of intense see-saw negotiations, though it must still be formally approved by the bloc and ratified by the European and UK Parliaments.
Mr Johnson tweeted: "We've got a great new deal that takes back control - now Parliament should get Brexit done on Saturday so we can move on to other priorities like the cost of living, the NHS, violent crime and our environment".
The British Parliament has rejected a Brexit deal three times in the past.
He will have to climb some more to get the Northern Ireland's Democratic Unionist Party on board. Scottish National Party leader Nicola Sturgeon said on Twitter that her party will not vote for the deal.
"If we have a deal, we have a deal, and there is no need for a prolongation", he said. He has apparently told European leaders that he is "optimistic" that he will be able to get the deal passed by parliament.
Johnson's 10 Downing Street office put it even more succinctly with the mantra: "New deal, no deal but no delay".
EU Brexit negotiator Michel Barnier said he and his fellow Frenchmen would not forget "Britain's solidarity during the darkest hours", a reference to their alliance during World War II.
The pound also jumped against the euro, and was trading above €1.16.
He said the most recent breakthrough came after Johnson met Irish prime minister Leo Varadkar ten days ago, and negotiations were given a new push.
"Faced with the alternative, we would rather (have) a very short extension so there could be a general election, and a Leave alliance could win a thumping majority and then leave on a clean-break Brexit because we would then have the numbers in the House of Commons".
"Squaring this circle", as Barnier described it, means the United Kingdom tariffs will apply to goods entering from third countries that are not at risk of entering the single market, and a list of exempted goods will be drawn up. Immediately complicating matters was Johnson's Northern Irish government allies which didn't waste a minute to say they could not back the outline deal because of provisions for the Irish border.
"As things stand, we could not support what is being suggested on customs and consent issues, and there is a lack of clarity on VAT (value-added tax)", DUP leader Arlene Foster and deputy leader Nigel Dodds said in a statement.
He said that during a phone call with Commission President Jean-Claude Juncker this morning, Johnson had expressed confidence that he could get the deal through the House of Commons.
One lawyer who opposes Brexit launched legal action to prevent Saturday's vote, arguing that the proposed changes to customs formalities in Northern Ireland breach British law. No EU tariff will apply to personal goods either.
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