Cockney rhyming slang is a form of phrase construction. The construction involves replacing a common word with a rhyming phrase of two or three words and then, in almost all cases, omitting the secondary rhyming word (which is thereafter implied), in a process called hemiteleia,making the origin and meaning of the phrase elusive to listeners not in the know. Translation: slang spoken to exclude others. This is prevalent in the East End of London. But you will hear it all over Great Britain. There are TONS. Here are a few.
lies=pork pies. Or you would say, I think you are telling pork pies/porkies. You are basically calling someone a liar. Yikes
mate=China plate (so you say ‘china plate’ when you mean to say ‘mate’)
telephone=dog and bone
stairs=apples and pears (this is pretty common and I hear it on the daily)
wife=trouble and strife (hmmm…I wonder which sex came up with this one?)
deaf=mutton jeff (‘are you mutton jeff?’ seems more polite than saying ‘are ya deaf?’
Like I said, there are tons more but these seem to be the most common. Try slipping them in your everyday convo and see what happens!