Some critics say you can tell how good a restaurant is based on how well kept their toilets are.
For one Instagram user, it is London's restrooms in particular that the photographer is determined to get a handle on.
Going by the name Trap_Adviser, the anonymous snapper began to post pictures of toilets in London and other cities, quickly gaining over 2,000 followers on the image-driven social media website.
Ranging from a commentary on the cleanliness to signs about loos, the instagramer has taken to picturing it all, giving followers the low down on the city's best bathroom facilities.
Whilst some posts are poetic in their description of lavatories - "porcelain in the park" to illustrate the toilets in Hackney Park - others are short and simple.
"Comparing and sharing the facilities in London and further afield" is the aim, and followers have taken an immediate liking to the pictures, sharing their own memories from their visits.
One user even commented: "Follow this account so you know where is safe."
London's restaurants are home to some of the world's most lavish toilets, with bars such as Mayfair's Sketch regularly making an appearance on Instagram with their spaced themed toilet pods.
