BRUSSELS (Reuters) - British Prime Minister Theresa May failed to secure a breakthrough in Brexit talks on Monday with European Commission President Jean-Claude Juncker.  Here is a timeline of the coming 10 days that will determine whether Britain avoids further costly delays in giving business assurances of a smooth exit from the European Union and of free trade with its biggest market in the future: May wants the EU to open the second phase of Brexit negotiations concerning relations after Britain s withdrawal on March 30, 2019. The EU will only do that if there is  sufficient progress  in agreeing  divorce  terms, notably on three key issues: a financial settlement, guaranteed rights for EU citizens in Britain and a  soft border  with Ireland. A deal on money is effectively done, EU officials said last week. There are indications of agreement on citizens  rights. But opposition from key allies in Northern Ireland to treating the province differently from the mainland in a bid to maintain on open EU land border with Ireland scuppered a deal on Monday. As part of the  choreography  for a political deal, the EU set May an  absolute deadline  of Monday to provide new offers in time for the other EU leaders to approve a move to Phase 2 at a summit of the EU-27 on Friday, Dec. 15. Now, however, that has been pushed back by a few days, EU officials have conceded.  May is pushing for a simultaneous, reciprocal guarantee from the EU of a soft transition and future trade deal, which she may use to show Britons what her compromises have secured. The EU wants to have firm British offers which the 27 can discuss before leaders commit. The result is some complex dance steps: Tuesday, Dec. 5 EU summit chair Donald Tusk, having canceled a visit to Jerusalem, had expected to call around EU leaders to discuss common guidelines for launching trade negotiations with Britain. This and a series of other steps are now on hold. Monday, Dec.  11 EU-27 sherpas meet to prepare the summit. Tuesday, Dec. 12 EU affairs ministers of EU-27 meet to prepare summit. Thursday, Dec. 14 4 p.m. - May attends routine EU summit in Brussels. Defence, social affairs, foreign affairs and migration are on the agenda. Friday, Dec. 15 After May has left, EU-27 leaders hold Brexit summit. They could take one comprehensive decision on Phase 2 or break it down into separate ones on the transition and future ties. If May delays a divorce agreement until the summit, perhaps to show voters at home her resolve, this may delay opening trade talks. January - Outline of EU transition offer may be ready, under which Britain retains all rights except voting in the bloc, and meets all its obligations until the end of 2020. February - After agreeing their negotiating terms, EU-27 may be ready to open talks with London on a free trade pact that Brussels likens to one it has with Canada. The EU estimated at some 60 billion euros ($71 billion) what Britain should pay to cover outstanding obligations on leaving. EU officials say there is now agreement after Britain offered to pay an agreed share of most of the items Brussels wanted, especially for committed spending that will go on after 2020. Both sides say there is no precise figure as much depends on future developments. British newspaper reports that it would cost up to 55 billion euros sparked only muted criticism from May s hardline pro-Brexit allies who once rejected big payments. Irish Prime Minister Leo Varadkar said on Saturday that London would be paying the EU 60 billion euros on Brexit. Barnier is still seeking a commitment that the rights of 3 million EU citizens who stay on in Britain after Brexit will be guaranteed by the European Court of Justice, not just by British judges. May has said the ECJ should play no more role in Britain. But the issue could be vital to ensure ratification of the withdrawal treaty by the European Parliament. EU diplomats say a compromise may let British courts refer cases on citizens  rights to the Luxembourg-based ECJ on a voluntary basis. Irish premier Leo Varadkar said London agreed on Monday that Northern Ireland would remain in  regulatory alignment  with the EU, and hence the Irish Republic, to ensure there was no  hard border  with police and customs checks that could disrupt peace. However, a hostile reaction from May s pro-Brexit and pro-London allies the Democratic Unionist Party (DUP), on whom she depends for her slim parliamentary majority, caused May to hold off agreeing the package deal with Juncker. The DUP and many in May s own party fear that means separating the province from the British mainland - or forcing EU rules onto the whole of the UK. Leaders of mainland regions Scotland, Wales and London leapt on the deal to demand similar freedom to perhaps remain in the EU customs union or single market, giving May a new headache.  Varadkar said he is willing to see changes in the text   but not that would change its actual meaning. 
Factbox: Countdown to Brexit breakthrough?