Help Please!!

[JodieMay10]

Hello, I didn’t know if anyone could help me please. I’ve owned my A1 for a year now and the other day I noticed a long rubber pipe sticking out from underneath my bumper just under the drivers side wheel arch at the back. I’ve shown a few people and they don’t know what it is, so I thought I’d ask on here! It was sticking out about 4 inches and I had to push it back in and tuck it up under the bumper. If anyone could give me some answers it would be greatly appreciated as I feel like a bit of a wally taking it to a garage and asking haha. In the picture I’ve provided it’s the grey tube tucked away. Thank you in advance for any help!