This is one of the four Tate galleries (the others are Tate Modern also in London, Tate Liverpool and Tate St Ives (guess where they are).
Situated on Millbank, it's about a ten minute walk along the River Thames from Westminster area, so it combines nicely with a look at Big Ben, Houses of Parliament and Westminster Abbey.
Entry to the Gallery is free (although there may be a special exhibition for which there is a charge), although there are boxes around for you to leave a donation. It is open every day, 10am to 6pm, with a late night opening until 10pm on the first Friday of each month. The only closing dates are 24, 25, and 26 December.
It houses British art (but not all the artists are British, if that makes any sense to you) from 1500 to the present day, so it is a fantastic gallery to visit if you want a taste of a variety of eras and styles. Few other galleries have such a wide range, from 16th century portraits to the sort of modern installations that make me stand there scratching my head.
Most of the works are grouped by artist or era so you can also just hone in on the areas of interest to you if you want a shorter visit. You can get a good general wander round in a couple of hours, dive in for a quick cultural treat for 15 minutes or so, or spend hours gazing at one piece of art. There are plenty of seats and benches around, along with a cafe and gift shop, and we checked out the toilets too (nice and clean).
We visited on August Bank holiday but it wasn't too crowded, which was surprising, but very welcome. The gallery runs a programme of talks and introductory tours, has a audio tour for hire, and also has a family trail through the galleries with activities for children. for example, in one room, they could listen to noises through headphones and had to decide which painting they related to.
We are very lucky to have access to such fine art, free of charge, in the UK and I'd recommend this as an excellent 'starter' gallery for those who haven't been to one before, as well as to the real enthusiasts.