Londoners will be asked if toilet provision in their city has really gone down the pan.
Londoners can have their say on the state of public loos
The London Assembly is holding a public meeting to find out if, and how, it can improve on current facilities.
It says although there are 500 council-run loos the public think they are few and far between. Only 93 of 273 Tube stations have public toilets.
Those who attend the meeting at City Hall can express their views using an electronic voting system.
They will be asked about ease of finding a public toilet, their cleanliness and accessibility, how much is a reasonable charge for using one and should cafes and restaurants allow anyone to use their loos.
Assembly member Joanne McCartney who is leading the investigation said: "For many Londoners, knowing where the nearest toilet is - whether it's provided by the local council or a local café - is a big issue.
"We want to hear Londoners' views on improving the quantity and quality of all public toilets."
The meeting begins at 1400 GMT on Monday.