The shop lost $3000 worth of Christmas hams, meats and bacon in a robbery a few days before Christmas 2012. To avoid any chance of losing this year's Christmas stock, the new owner, who wants to be known only as Simon, is guarding his stock of 100 hams and other expensive Christmas meats by sleeping in a ham-mock in his prep room.

Describing himself as "the cheapest security guard I know", Simon said he would be ready for anyone who threatened his Christmas meats. Sleeping at work wasn't bad apart from the noise of the refrigeration unit. "We are just a little old suburban butcher shop, with not much security," he said.

Simon is a victim of what the Nerida Campbell, a curator with the Justice and Police Museum, described as a "seasonal crime, the theft of Christmas hams".

These thefts have been reported in Sydney for the past 150 years, usually starting in November and peaking in mid-December. Only this week, ham heists were reported in New Zealand and Canada as butchers like Simon stocked up with expensive cuts of Christmas meats and hams. Simon has more than 100 hams at about $140 each in stock, and other cuts of entire eye fillets and rumps. Other butchers around Sydney are leasing extra storage units to feed the Christmas hordes.

Traditionally some crimes were small and involved only a single ham being stolen from a suburban shop, said Ms Campbell, who works for Sydney Living Museums which runs the museum. Others were targeted at "known ham repositories", such as the Metropolitan Ice and Cold Storage Company in Harris Street. It lost 126 large hams during a daring robbery in 1945, she said.

A similar theft occurred just before Christmas 1931 when a lorry delivering hams returned to his truck to find the remaining hams had been stolen.

Another case heard by the Water Police Court hinged on whether looking longingly at a ham was evidence of guilt.

In 1884, Michael O'Brien was alleged to have stolen a ham from an Oxford Street grocer after he had been observed "looking intently at the hams on display".

The magistrate threw the case out stating "that looking at a ham three or four times did not constitute a felony", a sentiment with which Ms Campbell agreed.

Simon said it was no laughing matter having a shop full of hams stolen on Christmas Eve.

According to NSW Police, no thefts of hams had been reported recently. If they had, they were likely eaten by now.

Hams (or legs of pork) in police custody, 1945. NSW Police Forensic photography archive, Justice & Police Museum.