Is is better to have american cash on your person or no cash with bank statement

Since I never flew out of the country before as an American citizen, I have tons of questions.

I am not a frequesnt flyer so I do not know lots of details.

when faced with the IO at the desk:

Is it better to have no american 'cash' on your person and just have your atm bank statement with you to show you have a bit of savings for your trip?

OR is it better to take out some cash to have on you plus your bank statements?


(Where in the airport do you exchange your American currencies into cash pounds? Is it AFTER you have been cleared by the IO or before?)

You should have your last few months of bank statements when you go to enter the UK to present to the IO to show that you have funds to cover your stay in the UK. You can bring some $$$'s if you want to but you'll just need to exchange it for £££'s when you arrive. It really doesn't matter what form your funds are in, you just need to have them cash or card.