A world-class gallery or museum. The coast, a world-class gallery or museum, London, a place outside London, the countryside, a pub. A supermarket, an old university town, a stately home, a performing arts event, a theater, a concert, a festival. Fish and chips, preferably by the sea, a pub meal, a grilled dinner.
Curry, tea, British-style, real beer. You can enjoy most of the things on this list just about anywhere in the UK or on your way somewhere else. London is chosen as the specific destination, as most visitors to the United Kingdom spend some time there. Galleries and Museums in London I can't imagine coming to Great Britain and not going to London, a world-class city packed with just about anything you want to see or do.
It's not going to be cheap, but you already knew that anyway. London: be sure to go here. And make sure that you not only go here, but also go to other places. (This is Buckingham Palace) As great as London is, it's a unique place in England and the United Kingdom and very different from the rest of the country.
Make sure to get away for a while, if not for an important part of your trip, at least for a day or two to see what most of the country other than London is like. It's not London (it's the Lake District). The theatre and performing arts scene in Great Britain is very lively. Theaters in London's West End are considered to be among the highest quality commercial theatres in the English-speaking world.
There are always a lot of plays and musicals at any given time and they change regularly, so it's almost certain that there will be something that interests you. If classical music is your thing, the Proms are held every summer for around eight weeks starting at the end of July, where you can see daily concert performances at the Royal Albert Hall in London and, to a lesser extent, at other venues in London and, sometimes, in other parts of the country. Shakespeare's Globe Theatre, on the banks of the Thames, in London. Whether it's Shakespeare or something more modern in a traditional or modern setting, London theaters have all the options.
Image courtesy: Maschinenjunge, used under a CC by SA 2.0 license A bar meal: Pubs can offer good quality food with an authentic atmosphere between tables and drinkers or they can have a separate restaurant area, they are generally more relaxed than restaurants that are not bars. You can also have a couple of extra drinks at the bar afterwards. In summer, sit in the garden if you have one. Afternoon tea: at the Ritz or Savoy in London, if you want to go further afield, or in many other places where tea is served if you want to enjoy a full experience.
I prefer a creamy tea with rolls, jam, whipped cream and, preferably, fresh strawberries with plenty of Darjeeling tea to accompany it. Lots of places, lots of options A pass for 1 to 10 consecutive days provides excellent affordable access to more than 80 of London's top attractions. Britrail travel passes, discounted rail passes for foreign visitors, unlimited train travel every day of travel around England, Scotland and Wales.