* EU to meet on Nov. 25 to approve deal
* Opponents maul May's deal at home
* May gets cabinet approval for deal
* UK junior minister resigns
* Lawmaker says DUP will vote against May (Adds DUP comments)
By Jan Strupczewski and Sarah Young
BRUSSELS/LONDON, Nov 15 (Reuters) - European Union leaders will meet on Nov. 25 to endorse a divorce deal but British Prime Minister Theresa May was mauled by opponents, allies and mutinous members of her party who warned the Brexit agreement could sink her premiership.
May won the backing of her senior ministers for the deal after a five-hour meeting on Wednesday though she now faces the much more perilous struggle of getting parliament, which has the final say, to approve it.
"If nothing extraordinary happens, we will hold a European Council meeting in order to finalise and formalise the Brexit agreement," European Council President Donald Tusk said after meeting EU chief Brexit negotiator Michel Barnier.
More than two years after the United Kingdom voted in a referendum to leave the EU, May said the deal was the best the world's fifth-largest economy could hope for and the other options were leaving with no deal or thwarting Brexit.
But in a sign of just how hard the vote in the British parliament might be, Shailesh Vara, who backed EU membership in the 2016 referendum, quit on Thursday as a junior minister in May's government.
"I cannot support the Withdrawal Agreement that has been agreed with the European Union," Vara said as he resigned as a Northern Ireland minister.
"We are a proud nation and it is a sad day when we are reduced to obeying rules made by other countries who have shown they do not have our best interests at heart. We can and must do better than this."
A lawmaker from the Northern Irish Democratic Unionist Party (DUP) which props up May's minority government, said the party would vote against the deal.
Asked in an interview with BBC Radio Ulster whether the DUP would vote against, Jim Shannon said: "We certainly will ... We feel very much betrayed."
Nick Timothy, one of May's former chiefs of staff, wrote in the Daily Telegraph newspaper: "When parliament rejects the prime minister's proposal, as surely it will, there will still be time for ministers to negotiate something better."
Timothy, who resigned after May's gamble on a snap election that lost her party its majority in parliament, said Britain should use its security contribution as a bargaining chip to get a better deal.
May will give a statement to parliament on Thursday on the deal which she hopes will satisfy both Brexit voters and EU supporters by ensuring close ties with the bloc after Britain leaves on March 29.
The ultimate outcome for the United Kingdom remains uncertain: scenarios range from a calm divorce to rejection of May's deal, potentially sinking her premiership and leaving the bloc with no agreement, or another referendum.
Getting a deal through parliament will be difficult. She will need the votes of about 320 of the 650 lawmakers.
"The parliamentary arithmetic has looked tight for some time," Goldman Sachs said in a note to clients. "It now looks tighter, given signs of greater unity among those who object to the draft agreement."
"We're in the Brexs**t - Theresa May's soft Brexit deal blasted by ALL sides," read the headline in The Sun, Britain's best read newspaper. (Additional reporting by Amanda Ferguson in Belfast; Writing by Guy Faulconbridge; Editing by Janet Lawrence)
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