Not mine, Merriam-Webster's. Mine are guv'na, gor blimey and bollocks. Jiggery-pokery... nothing at all what I thought it was. Ditto boffin (the apostrophe makes a difference: boffin'). I thought pukka was a type of bead.
From M-W: "Although Merriam-Webster is a dictionary of American English, it contains a range of words rarely heard outside Britain. Here are some of our favourites."
PRAT: a stupid or foolish person
"Everyone's feeling a bit summery this morning, with a few rays breaking out over Britain and some of you lot daring to break the 'anyone who wears sunglasses in April is a prat' rule that we just made up." – 3am.co.uk, April 6, 2011
TWEE: affectedly or excessively dainty, delicate, cute, or quaint
"Micmacs [is a] ramshackle and unbearably twee French comedy." – Daily Mail Online, February 26, 2010
(Twee + Prat = Twat, a quaint idiot? - C.)
KNACKERED: tired, exhausted
"Went for a 4-miler and then when I got back from work we took the kids swimming. Nice and knackered now." – blog post at SoreLimbs.co.uk, January 18, 2011
JIGGERY-POKERY: dishonest or suspicious activity; nonsense
"[Greece] flouted European Union rules on the limits to budget deficits; its national accounts were a moussaka of minced statistics, topped with a cheesy sauce of jiggery-pokery." – Jeff Randall, The Telegraph, May 20, 2010
PLONK: cheap or inferior wine
"Fine diners are drinking premier cru wines at plonk prices as a bring-your-own booze revolution gathers pace in Britain's best restaurants." – Robert Booth, The Guardian, June 20, 2010
CHUNTER: to talk in a low inarticulate way: mutter
"Tell me about it. I was chuntering on last night about *padded* training bras." – michlan on Twitter, April 13, 2011
WHINGE: to complain fretfully: whine
"I shall have one pint of beer less every time I'm in the pub, and I might occasionally whinge about the rises in the cost of living outstripping my wages." – blog post on A Dull Day at Work, April 2, 2011
GORMLESS: lacking intelligence: stupid
"Gormless, unhelpful and poorly trained shop staff create merry hell for customers who are simply exercising their legal rights to a repair, refund or replacement." – Sam Dunn, Two Pennies Worth blog, March 22, 2011
BOFFIN: a scientific expert and especially one involved in technological research
"Brain boffins at University College London have made a major breakthrough in the ongoing effort to bridge the gap between man and machine." – Rik Myslewski, The Register, April 11, 2011
PUKKA: genuine, authentic; first-class
"... the record-breaking Sri Lankan [cricket player] has always shown himself a pukka gent...." – William Langley, The Telegraph, July 24, 2010
More at Merriam Webster.