Definitely not the Isle of Wight is 147 square miles, if my math is correct thats a little over 4 billion sq feet so if each person only occupied 12X12 inches you would have 2.5 billion people left over.
We should bear in mind that prior to the mid 1970s the world population was less than 4 billion and before 1960 it was 3 billion, so the statement would have been true at some stage in our 'recent' history.
According to the 'Encyclopedia of Britain', the Isle of Wight covers 380 square kilometres or 147 square miles. There are over six billion people in the world now. Given that they are all different sizes, let's imagine that the average 'area' required for each standing person is about � a square yard. I'm no mathematician, so I suppose I'll be shot down in flames here, but I calculate that 147 square miles = just over 441 million square yards...ie space for about 880 million people. That's not even one billion, never mind six! The Isle of Man is a bit bigger at 227 square miles, but there is still nowhere near enough room, nor is there if you shared the people out around both islands. Based on the figures above, the area required would be about 1000 square miles.
My American math closely resembles that of the previous posters....you may, also, need Nebraska!
Coincidentally, I own Nebraska and am putting it on the Real Estate Market, this week ONLY! for a mere $42,000! American dollars, that is.....30K Euros or 12 pounds, English.....