Vipassana meditation was the original technique of self purification taught by Gotama the Buddha in India around 500 BC. It is currently taught in the tradition of Sayagyi U Ba Khin and SN Goenka, in the UK at the Herefordshire meditation centre -known as Dhamma Dipa, and at the Suffolk Centre- known as Dhamma Sukhakāri (as well as in other centres around the world). The technique is taught, and the centres are run, entirely on donations given by students that have completed a course and would like others to benefit like they have. Even the people cooking and running the place are doing so ‘for the good of others’, without being paid to do so, which creates a very special and unique environment.
The technique is taught in the form of 10 day silent meditation courses. These are very well structured with instructions and guidance all along the way, as well as evening discourses that help to clarify different aspects of the practice. There are teachers and managers that you can see about any problems you may have during the course. I can honestly say that going on these courses is by far the single most fruitful thing I have ever done in my entire life.
You can learn more about Vipassana meditation and book courses at https://www.uk.dhamma.org. Courses get filled up very quickly (often within one or two hours), so you need to book well in advance and be ready to do so right after the booking becomes available.
The Vipassana Research Institute has a useful page about What is Vipassana. You may also like to have a look at their webpage What is Anapana Meditation. This is especially useful for those who for whatever reason feel they can’t take the time to do a full 10 day course at the moment, but would like to start practicing at home now. At the bottom of the Anapana Meditation page you can watch a short 20 minute video clip of SN Goenka’s Mini Anapana Discourse, in which he teaches you to practice Anapana Meditation in what he affectionately calls the Kindergarten of Vipassana.