Models Samia (left) and Domonique in dresses made of shrimps and citrus fruit at the first-ever Australian garden to appear at the Chelsea Flower Show in London. (AP)

London, May 24 (Reuters): Homeowners who strategically use roses, cockle shells and high fences in their gardens will provide a first line of defence against burglars, British police at London’s annual Chelsea Flower Show said.

To illustrate the point, the Metropolitan Police have constructed a show garden at this year's London flower fest, the place to be seen at the start of the British summer calendar.

“Traditionally people have believed that their defence perimeter began at the house. We are pointing out that it in fact starts at the garden fence,” detective inspector Paul Anstee said at the premier social event.

Garden fences should be at least 1.6 metres high and topped by something prickly, sheds should be double-locked, outside lights on all night, pathways made of something that makes a noise and garden ornaments alarmed, Anstee said.

There is even a climbing rose specially named “New Scotland Yard” after the Metropolitan Police Service’s London headquarters, and the garden path is made of cockle shells which make a crunching noise when stepped on. “Instead of barbed wire on top of the fence we suggest you could plant climbing roses or holly — something aesthetic used in a creative way to supplement your barrier,” Anstee said. “It makes it secure and is attractive as well.”

Theft of garden tools and ornaments is a common nuisance during the northern hemisphere summer and also a danger, since such stolen tools often provide would-be thieves with a means of access to the house. “We show how you can secure garden ornaments or wire them up so they set off an alarm if they are moved,” Anstee said.