Definition: Given a document, generate a short title of the document. The title should convey the main idea/event/topic about which the document is being written. Note that URLs in the text have been replaced with [Link].
Input: British Prime Minister Theresa May  has said that  her  government is "proving the doubters wrong" after European Union leaders agreed that Brexit negotiations can finally move on to their next phase in the new year.
Leaders of the other 27 EU nations gave a boost to  May  on Friday when they declared that talks over Britain's exit can proceed to the issues of transition and future relations.
Writing in two Sunday newspapers   May  also struck a defiant note and said  her  Brexit plans won't be "derailed" by anti-Brexit campaigners.
May  who is already struggling to maintain  her  authority amid the fractious exit process  suffered a significant political defeat in Parliament on Wednesday when the House of Commons voted to give lawmakers the final say on any Brexit agreement.

Defiant Theresa May: UK 'proving Doubters Wrong' on Brexit