Something to pat in your back pocket that doesn't clink
Asda Wal-Mart has mounted a condom sales push over Christmas with discounts on packs of 10 and 12. The move is in response to concern over the rise in sexually transmitted diseases in the UK.

Based on historical sales analysis, the retailer expects the best response to the offer to come from its Chesser store in Edinburgh. However, it predicts condom sales in Watford to be the most deflated.

Asda non-food director Tony Page said: 'Through our condom rollback, we are trying to illustrate that protection against sexually transmitted infection is easy, even more affordable and accessible.'

Some facts you never knew about condoms

As early as 1,000BC, the ancient Egyptians used a linen sheath for protection.

The Chinese are known to have used oiled silk paper.

The oldest known condoms were found in Birmingham, dating back to 1640. They were made from fish and animal gut.

In 16th century Italy, Gabrielle Fallopius published the first written description of prophylactic use. He conducted an experiment with 1,100 men, using a sheath made of linen. None of them became infected with Syphilis.

In 19th century Japan, condoms were made from thin tortoise shells and leather.

Mass production of rubber condoms began after the invention of vulcanisation in 1844, a process that turns crude rubber into a strong elastic material. They were still as thick as an inner tube.

Latex manufacturing improved steadily, and by the 1930s condoms were almost as thin as those on offer today.

The reservoir tip was introduced to the condom in the early 1950s.

In 1994, Polyurethane started to replace latex as the base material for condoms, leading to the creation of the female condom.