couldn't organise a bun fight in a bakery

(Someone) is utterly incompetent or unable to arrange things successfully; (someone) can't even manage or carry out the simplest of tasks. Primarily heard in UK, Australia. I'm not surprised Marie's event was a disaster—she couldn't organize a bun fight in a bakery! The leaders of this country couldn't organise a bun fight in a bakery, so why on earth are people trusting them to handle this situation properly? No wonder the strike failed. Those dipsticks couldn't organise a bun fight in a bakery!