* No need for treaty changes, Van Rompuy says in London * EU exit would cost Britain dear * Says euro zone has "artillery", but could be aftershocks (Recasts, adds quotes and outside comment) By Guy Faulconbridge and Andrew Osborn

European Union leaders agreed Friday the first ever cut in the bloc's budget after all-night talks driven by sharp differences over priorities for the next seven years. "Deal done!" summit chair and EU President Herman Van Rompuy said on Twitter after more than 24 hours of tough talks between the bloc's 27 heads of state and government. "There's a lot in it for everybody", he added a short time later, while emphasising that the 2014-2020 austerity budget embodied "a sense of collective responsibility from European leaders."

EU leaders edged Friday towards a compromise on the bloc's budget for the rest of the decade at an all-night summit, Britain pushing big spending cuts while France fought for funds to slash record European unemployment. Fifteen hours after the meeting began formally in Brussels, European Union president and summit chair Herman Van Rompuy put new figures to the leaders of the 27 member states that would mean a 908.4-billion-euro ceiling for actual payments, several EU sources said.

EU leaders opened tough talks over a trillion-euro budget hours late Thursday amid sharp differences over spending cuts and investment for growth and jobs. The meeting got underway almost six hours behind schedule as leaders of the 27-nation bloc held backroom talks and Britain, notably, pressed for huge cuts in EU spending over the rest of the decade. EU president and chair of the talks, Herman Van Rompuy, said as the summit began that he had held productive discussions in recent weeks and was "confident that around this table we can now settle on a final compromise."