European Union leaders warned the British parliament not to wreck Theresa May\u2019s Brexit deal, saying a package agreed with the prime minister on Sunday was the best Britain will get. \u201cThose who think that, by rejecting the deal, they would get a better deal, will be disappointed,\u201d European Commission president Jean-Claude Juncker told reporters after the 27 other EU leaders formally endorsed a treaty setting terms for British withdrawal in March and an outline of a future EU-UK trade pact. Asked whether there was any chance Brussels would reopen the pact if an alliance of pro- and anti-Brexit forces votes it down in the House of Commons, Juncker simply stressed \u201cthis is the best deal possible\u201d \u2014 although summit chair Donald Tusk sounded more guarded, saying he did not want to consider hypotheticals. May used a post-summit news conference to make a sales pitch for her plan, telling television viewers at home that it was the \u201conly possible deal\u201d, offering control of UK borders and budgets while maintaining close cooperation with EU regulations that was good for business and the security of the broader region. \u201cIn any negotiation, you do not get everything you want. I think the British people understand that,\u201d said May, who arrived after the endorsement to voice hopes for continued close ties. Parliament's vote could open the door to a \u201cbrighter future\u201d or condemn the country to more division, she said. \u201cI will make the case for this deal with all my heart,\u201d she added, declining to answer whether she would resign if parliament rejects it. Amid praise for Michel Barnier\u2019s team of negotiators for bringing home a deal after 18 months of gruelling talks, Juncker said it was \u201cno time for champagne\u201d, as one of Europe\u2019s great powers walks out after its 2016 Brexit referendum. The harder work of building new relations now lies ahead, he added. European Council President Tusk said the bloc was determined to have as close as possible a partnership with Britain, which has long been sceptical about EU integration: \u201cWe will remain friends until the end of days. And one day longer,\u201d he said. The 27 leaders took barely half an hour to rubber-stamp the 600-page withdrawal treaty, aimed at an orderly exit on March 29 to be followed by two to three years of a status-quo transition period. The outline of a future trading and security partnership was just 26 pages long. May\u2019s critics say it leaves Britain tied to EU regulations that it will no longer have a say in setting.