Apple's newly released iPad 3 is available with a LTE 4G option but the radio frequencies supported are incompatible with those expected to be offered in the European market.
The European WiFi/4G iPad 3 is essentially the same as the US AT&T version which means that it supports 4G LTE on the 700MHz and 2100MHz bands versus the 800, 1800 and 2600MHz bands planned in European territories.
That said, given that LTE hasn't yet launched in several countries including the UK, the 4G iPad 3 still supports the older 3G standards including the nippy HSPA+ standard on virtually every band where those technologies are used 850, 900, 1900, 2100 MHz.
Meanwhile in the US, Apple's iOS 5.1 update has apparently fallen into line with the marketing departments of the local mobile carriers and has switched out the 3G icon for a 4G icon when connected to AT&T's HSPA+ network.
In fact LTE being called 4G itself is already a corruption of the original ITU standards body's definition of 4G but now it seems changing a digit is easier than rolling out a new fancy network so they've taken to calling HSPA+ 4G in the US as well. Those crazy Americans.
So far that hasn't quite caught on in the UK, most likely because European press traditionally has somewhat sharper teeth and wouldn't let operators get away with it.
British operator Three already moved to clarify some misleading reports about a 4G network arriving this year, pointing out it was '3.5G' HSPA+.
The bottom line is that if you want mobile connectivity on your 'new iPad' then the 4G version will go as fast as any British mobile network (42Mbps) until the arrival of actual 4G LTE - and it'll nicely show you a 4G icon anyway, and that's all that matters right?