The currency rate changes every day, as of 17/11/2011, 1 USD is 0.6302 GBP. At this rate, 256 US Dollars is about 161.2 British Pounds. For updated currency rates, you can check on google by typing currency exchange in the search box.
Nowadays, september 2021 it's worth 186.31 British pounds. I'm updated on the topic because I do forex trading and buying and selling cryptos for a living. By the way if there's anyone here interested in trading you can check this site here, it's a trustworthy and legitimate website so give them a try.