Lithuanian President Dalia Grybauskaite arrives on December 13, 2018 in Brussels for a European Summit aimed at discussing the Brexit deal, the long-term budget and the single market. John Thys/Pool via REUTERS

BRUSSELS (Reuters) - If Britons would just make their minds up about what they want for Brexit, the European Union will help make it happen, one EU leader said in a light-hearted tweet as a pre-Christmas summit got under way.

“Brexit Christmas wish: finally decide what you really want and Santa will deliver,” Lithuania’s ever pithy president, Dalia Grybauskaite, tweeted as Prime Minister Theresa May began 24 hours of meetings with her 27 EU counterparts in Brussels.

Having agreed a treaty last month to ease Britain’s path out of the bloc in March, the EU was exasperated that May failed to get the package through parliament this week and has come to the summit seeking tweaks that they show little sign of giving her.

May survived a confidence vote by her Conservative Party on Wednesday, but a mutiny by more than a third of her lawmakers indicated parliament was heading toward deadlock over Brexit.