ah fuck, I can't believe you've done this. 

A statement of frustration said when one is about to say something and is interrupted abruptly; usually with a punch to the face.

Note: It has to be said in a non-enthusiastic, brittish, calm and polite manner, if you will.

Example:

Some guy: "Hello everyone, i'm here today to talk about... *PUNCHED IN THE FACE*

Same guy: "Ah fuck, I can't believe you've done this."

ah fuck, I can't believe you've done this. by JoãoPaulo November 13, 2007

I cant believe you have done this 

Total disbelief, British style

ah fuck, I cant believe you have done this

I cant believe you have done this by d4mn3d June 2, 2008

Ah fuck. I can't believe you've done this. 

Best response to being punched. Ever.

Guy #1: *Punches Guy #2 in the face*
Guy #2: "Ah fuck. I can't believe you've done this."

Ah fuck. I can't believe you've done this. by liMPiNMEdiC January 6, 2008

i can't believe you've done this 

Something uttered by British people after they've been suckered punched. Usually preceded by the exclamation "Aw fuck", and accompanied by a look of complete bewilderment.

British guy: Blah Blah Blah Blah
British guy's friend: *punches British guy in the face*
British guy: "Aw FUCK, I can't believe you've done this!"

i can't believe you've done this by Susake December 1, 2007

I Can't Believe You've Done This 

the new meme, originating from the infamous youtube video

http://youtube.com/watch?v=8lBO23Dh23I

pete: hey, say thanks to your mum for me
sam: aw fuck, i can't believe you've done this

I Can't Believe You've Done This by crincled January 8, 2009

You've Probably Done This... 

When you fall asleep immediately after ejaculating inside a female while still inside her, and she leaves you asleep on the couch, naked, for her roommates to see when they come back home.

The next morning after waking up naked on her couch, you call your buddy to tell him what happened and you start the story with "You've Probably Done This..."

You've Probably Done This... by Scott Meadow June 13, 2006

Ah Fuck I can't believe you've done this 

Expression of anger after someone has annoyed you

"Ah fuck I can't believe you've done this Barry why did you break my mum's lamp."

Ah Fuck I can't believe you've done this by Anti-hypofritz February 26, 2017