By Gareth Bayley for The Huffington Post.

Today, 19 August, is World Humanitarian Day. It’s invidious to choose among the most pressing humanitarian crises around the world. But there’s one very close to my heart: Syria. I work with my team across three countries – Lebanon, Turkey and Jordan – to help resolve the Syria crisis.

So far, the Syria crisis has claimed at least a quarter of a million Syrian lives. An estimated further 16 million Syrians are in need of assistance inside and outside the country. As the UN Secretary General’s Special Envoy for Syria recently pointed out, almost half of the country’s population – 12million men, women and children – have been forced to flee their homes. Syrians are now the largest refugee population in the world.

For the UK, the number one imperative is that this crisis ends. Syrians must be able to negotiate, agree and own a political settlement which leads to inclusive government and stability of the kind you can only get from governance both accountable to Syrians and legitimate in their eyes. By his actions, Assad has shown he cannot be a part of that.