￡200 won't be enough. I'm guessing from your previous questions that you aren't British and you will probably find that even if you had a debit card, it won't work in British ATMs because British cards use the chip and PIN system. British debit and credit cards have a visible chip on the front, so even in shops and stores we pay by putting the card into a terminal at the checkout and tapping in the PIN. I do that in the supermarket all the time.
I don't know where you heard from that we prefer cash but it isn't true. Visa and MasterCard are almost always acceptable. Just bear in mind any conversion charges you might get for using the card in a foreign currency. And it might help to tell the credit card company first where you're going so they don't get the idea that the card's been stolen and how come it's now being used in London?
But if you prefer cash, and it's handy for little things and shopping in markets anyway, you get the best exchange rate at a bank. Do NOT use a bureau de change. The "big four" banks you will find in London are Barclays, HSBC, Lloyds and NatWest. Go into any one of those and they will happily change dollars for pounds. Just go in and ask someone what to do - if one of their staff hasn't already asked YOU how they can help, which in central London is quite likely!
What I'm also used to (and this probably shows my age) is travellers' cheques (or travelers' checks if you spell it that way). American Express sell those and maybe your bank can get them for you. Change your money into those first, follow the instructions by signing every single one and keeping a note of the numbers, and they are theft-proof. If they go missing or get stolen, call the issuer and they will rush you replacements. American Express can do that easily in London. To convert them into cash, take them into a bank with your passport, sign them again in the marked space for a countersignature in front of the cashier (they have to see it's you signing them), and hand them over. Comparing the two signatures is a big security check and anyone trying to use a stolen travellers' cheque is going to have to be pretty good at forgery. Any you don't use, you can easily change back when you get home.
Your information is wrong. Unless you are paying for something extremely cheap, credit cards are preferred in most places. However, although there are facilities to sign the card slip, we use chip & PIN.
￡200 won't last long in London.
It's advisable to inform your card provider before leaving.
You can use a credit card in most places. But it really wouldn't help to have a card where you can withdraw cash- see if any pre-paid cards allow you to do that. 200 pounds won't last you long in London.
￡200 is nothing.
Use your cards, that's what British people do.
You heard wrong most people use cards ￡200 for two weeks is a joke
You can use your CC but you must tell your bank that you will be using it in the UK. They could block it if you don't.
