The anonymous crew member said water used for in-flight hot beverages is the same portable liquid that goes through the bathroom system, reports The Sun.

Describing jet lavatories as the “most disgusting places on the planet”, the attendant told Vice: “We recently had a test for E. coli in our water and it didn’t pass, and then maintenance came on and hit a couple buttons and it passed. So, avoid any hot water or tea.

“Bottled and ice is fine, of course.”

The airline mole also offered tips on how to join the Mile High Club.

They said: “Wait for service, when the attendants are in the aisle. Everyone’s busy and has a job at that point — and I don’t care what’s going on behind me then.

“There could be ten people in the bathroom and I wouldn’t be aware of it.

“On smaller planes, for shorter flights, the attendants aren’t watching you like you think we are. We’re on our phones in the back with the others or doing our jobs.

“We don’t want to be near that bathroom at any point in time and we’ll avoid it at all costs.”

This story appeared in The Sun and is reproduced with permission.