WASHINGTON, June 30 (Reuters) - Britain believes that there is more work needed to secure broader agreement on international tax commitments made by G7 wealthy democracies in the coming weeks and months, a senior UK official said on Thursday. Jonathan Black, Britain’s G7 and G20 sherpa, told an online forum hosted by the Center for Strategic and International Studies in Washington that it will be naturally more challenging to win consensus among G20 major economies for G7 agreements on a global minimum corporate tax and new methods of taxing large multinational firms. “The prize is huge. I think we are sort of optimistic, actually, that we will make progress on this but there’s still important work to be done in the next few weeks, and if not that, certainly, then, over towards the end of the year as well,” Black said. (Reporting by David Lawder Editing by Chizu Nomiyama) Our Standards: The Thomson Reuters Trust Principles.