UK billions aren't always the same as US billions. When billions are used in the UK, they often mean what the Americans would call trillions. It's important to get clarification on which billion they're actually using in figures because they still use both!

In the UK, fortnight is commonly used as a period of time, which is two weeks.

Dates in the UK (and most of the world) are formatted differently than the USA. Instead of Month-Day-Year, the day is first, Day-Month-Year and said for example "the 7th of November" (07-11-2011). Pay attention on important forms and food expirations!

While the UK Doritos brand nacho cheese sauce isn't very nice, Lidl does a nacho cheese sauce that is much better, their tortilla chips are good too.

If you're missing Campbells Chicken Noodle Soup, there is a close tasting substitute at Lidl called "Coquette Chicken Soup" in a 400g can.

Don't buy English mustard expecting it to be like French's American Mustard, it's hot and it'll blow your head off.

Driving while using a mobile (cell phone) or other communication device is illegal, can result in a fine and penalty points against your licence. Use a handsfree kit, only push buttons while it's in the cradle.

http://www.roadsafetyni.gov.uk/index/faqs/faqs-mobilephones.htm

In the UK, passengers in the back seat must wear seatbelts as well as those in the front seat. The person liable for failure to wear seatbelts is the driver.

The equivalent UK emergency number of 911 is 999.

You'll be asked if you require police, fire or ambulance.

Dial 101 for non-emergencies. http://www.police.uk/101