Santa Claus is controversial and arouses debate. For example:

Most people who enter Australia illegally get caught. Someone on a sleigh pulled by reindeer could hardly avoid detection. He'd be tracked by radar, detained by coast watch, and sent to a detention centre.

Regulations against importing plants or animals without permit would have Santa's reindeer confiscated and kept in quarantine or even destroyed.

Santa's sacks of toys would also be confiscated as he circumvented customs and imported them illegally.

Let's suppose Santa somehow gets past the navy and air patrols and starts delivering presents. He'd have so many homes to visit in Australia – about 5 million – he'd certainly be stopped by the police for speeding and face repeated fines.

Under the Motor Vehicles Act a vehicle must be registered and the driver possess a license to drive. Santa may be in the clear here since he would have an International Licence – although whether that covers sleighs and reindeer is uncertain.

Many people leave Santa a drink – wine, beer, port, etc. A few of these, let alone thousands, would put Santa's blood alcohol content above the legal limit. When the police further find he lacks a licence to fly his sleigh and doesn't use airports, but lands and takes off anywhere, he'd spend at least the first night in a cell.

Parking a sleigh on rooftops would also contravene council by-laws and lead to numerous parking fines.

Entering locked premises could constitute "break and enter". Santa's defence, if he had to appear in court, would be that he didn't enter to steal but had an implied invitation to enter and fill stockings.

However, if he gets his addresses mixed up and enters, for example, a skeptic's house then he's trespassing. Anyone who catches Santa trespassing could sue him. Initially the householder would either perform a citizen's arrest or phone the police.

Santa's list of names, especially the preponderance of children's names, would be suspicious. And how did he find out which children were well-behaved and which weren't without violating privacy laws or laws against stalking?

Traversing all Australia in one night would be tough on the reindeer. This would interest the Royal Society for the Prevention of Cruelty to Animals. Santa could be prosecuted.

The above legal obstacles constitute strong evidence that Santa Claus and his Christmas Eve activities are either mythical or much exaggerated.

However, first impressions are often misleading. There is other evidence suggesting Santa is active and hence, somehow, circumvents Australia's laws.

The North American Aerospace Defense Command – which monitors North American airspace – actually tracks Santa Claus by radar as he heads south from the North Pole and helps him stay on course.

Several years ago Defense Command officials admitted that their radar operators have done this since 1955!

Nowadays people can even follow Santa's progress on the internet and thus estimate the time of his arrival!

If we could find Santa's North Pole home the question of his existence would be settled. But it's never been found.

However, Santa now has a second base, still north of the Arctic Circle but more accessible than the North Pole.

In 1985 Mr Claus established Santa Claus Village. It's in a forest of firs and silver birches near Rovaniemi in northern Finland. Here tourists can visit Santa's log cabin office, post office and souvenir shop and even interview him. He receives one million letters per year.

Santa's address is: Santa Claus, 96930 Napapiiri, Finland.

The case for Santa may now appear proved. But before you run off to Woolworths to buy extra stockings to hang out you should read Father Christmas and His Reindeer. (Investigator 45)

That article investigates Santa Claus and his reindeer and their alleged activities from the perspective of biology and physics.