Setting up a UK bank account from home country?

I've been doing some looking around online (other ex pat websites) and some say that one can set up a UK bank account through your own home bank account. Is this true? Has anyone done it? It states that one needs copies of your passport, current bank statments of residence country, billing address as well as a copy of a utility bill. Then one can set up a UK bank account through one's current bank even before coming to the UK. Have I grossly misunderstood this or is this actually possible?

This is one of the websites that I read the information: http://europa.eu.int/youreurope/nav/en/citizens/factsheets/uk/consumerprotection/openingbankaccount/en.html