The United Kingdom has for a long time been a place where tourists want to come and take a vacation, both tourists from within the UK's Counties and Countries and further afield within the European Union, Asia, America, Africa and Australasia.
The UK has a vast history, which can be seen in every single corner of this little Country. It has been the home of many different races and fought over on countless occasions, in our most recent history the UK has been involved in many wars including the both world wars. At one stage the UK had the largest empire in the World and successfully controlled the waters with the most powerful naval fleet anyone had ever seen (at that point in time).
Many countries can trace their family tree back to the UK in some way or another, consider that many Scotch, English, Welsh, Cornish and Irish headed off to the new world to start a new life - several generations we would recognise these as residents of America and not the UK, however its highly likely that they have family in the UK or Europe. The same can be said for workforces - where there was a demand for skilled labour the UK resettled people far and wide, Cornish miners to New Zealand, Farmers to Australia etc.
The UK has had a big hand in the foundations of society and the writings of law, after all that great empire had outposts and rule over so many Countries which now have their own governments such as Canada and New Zealand.
The Queen of England Elizabeth II is still seen on coins throughout the world, namely the common wealth countries and I imagine she is the most portrayed person in the world - due to the number of different bank notes and coins she appears on. For this reason, her position of power, her generosity and everything that comes with being possibly the most recognised person alive today the royal family is a tourist attraction and good reason to visit the UK in its own right.
International travellers the world over have so many reasons to visit the UK, not just for the unpredictable weather conditions and all things considered traditional English, many people are connected to this little piece of land - just look at how many people live in the UK, it's one of the most populated places in the planet.