Borough Market is one of my favourite markets, if not my favourite market in London. It offers a plethora of delicious fresh food, vegetables, fruits, meats and more, as well as food vendors for an on the go lunch.
You can access Borough Market by bus and tube, but my favourite way to get there is by river boat! You can see information about river boats here on the tfl website, and plan your journey. This is by far the best way to kill two birds with one stone - sight see and travel!