English speakers manipulate sounds, syllables, affixes, words, phrases, and constructions in order to be funny. A pun is a form of word play that deliberately exploits ambiguity between similar-sounding words for humorous or rhetorical effect. 

Stephen Fry in ‘Fry’s English Delight’ explains the type of simple puns (word plays) that are called either homographic or homophonic puns: 

Homographic - exploits the meaning of words which look alike and usually sound alike (lots/lots).

Homophonic - exploits the difference in meanings of words which sound alike but have different spelling (pears/pairs).

The title of this research, 'British Rumour Rules!', is a homographic pun for those who hadn’t spotted it yet. I’ll let you work it out for yourself!

Why are they funny? Well sometimes you are just very impressed with the cleverness of it all. It’s about making links that are sometimes so obvious, if only you thought of it. It's about the speed with which the pun is created and the timing of it. The British are Pun Kings (pumpkins ... get it? ..oh well, I tried).

Here’s a great example of one, courtesy of Stephen Fry’s 'Fry’s English Delight’: ‘What is the definition of a mistress? .....Answer: Something between a Mister and a Mattress.’ Very silly but at the same time very clever and funny.