after the Lord Mayor's show

Etymology
From the proverb "After the Lord Mayor's show comes the dust-cart" (or "donkey-cart", or "shit-cart"). Bringing up the rear of the Lord Mayor's Show is a team to clean the manure of the pageant's horses.

Prepositional phrase

 * 1)  Said of a disappointing or mundane event occurring straight after an exciting, magnificent, or triumphal event.