The Age ran a particularly silly article today, under the headline, "At Heathrow it pays to be rich and organised". It describes the experience of an Australian who was turned around and sent home from Heathrow Airport in London. He had previously worked in the UK for two years, and on this occasion claimed to be going for a two month visit, with about £400 to fund the trip, and intending to stay with someone who could not independently confirm to UK Immigration that he was expecting a visitor.
The clear implication of the article is that UK Immigration is erratic and unreasonable, and that Australians may be summarily ejected from the UK for no good reason.
We can actually draw a simpler piece of advice from this tale. Any country can decide whom it will admit at its borders -- and Australia itself is stricter than most countries. Wise travellers can show that they can support themselves (£400 does not go far in London) and have strong ties to another place, so that they will leave the country without seeking work or using its health or welfare system.