A car, usually owned by a chav/pikey which has been crashed by its owner's idiocy, resulting in part of the body having to be replaced. Unfortunately for the pikey, the rotting vehicle has long been discontinued and parts for the car are scarcely available. The result is that the chav eventually settles for a totally different coloured car part to the rest of the car. Hence the car looks similar to a lego car which has been built by a deprived child who lacks a sufficient amount of same coloured bricks.
Chav: Aw bruv! Wuyyoo meen da XR3's bin discontinued?
Ford: We no longer manufacturer that vehicle, or any of it's parts. We're abandoning you as a customer.
Chav: Aw man. Watch! All my matez is gonna be sayin i has a lego car now when i has tah buy a part off eBayz.
Derived from the cliché "digging yourself into a hole" (In a conversation; where someone keeps saying things which make their own situation more and more awkward). "Drop the shovel" may be said to the person digging themselves into the hole by another member of the conversation concerned for the person's welfare, indicating that they should stop talking to avoid making the situation any worse. Created by the only Matthew Jones in Cardiff.
Jake: And I said to my girl, "Shut it, fatty!" Ha. But she got the joke.
Tom: Ha! It's funny because she is a little bit chubby!
Jake: No...that's not why it's funny. My girl's not chubby.
Tom: Nah but she's got a bit more cellulite than most.
Tom: Ok, it's not just cellulite I know. She must have an eating disorder righ-
Matt: DUDE. Drop the shovel.