They're cute, so it's not intrusive or scary

Sniffer dogs have been used in the UK to detect explosives, increasingly post-Madrid, but experts say the widespread use of beagles could be one answer. The dogs, made famous by cartoon character Snoopy, have been a hit at US airports such as Washington Dulles.

"Beagles are delightful and everyone goes 'Aaaah, they're cute, so it's not intrusive or scary," says security expert Bob Ayers, associate fellow of international think-tank Chatham House. "They are in keeping with the British tradition of policing - non-intrusive and non-threatening, unlike mastiffs or Rottweilers."

"I'd suggest using dogs in increasing numbers would help, but I doubt whether it would stop, say, someone getting a bus at Hammersmith."

The handler or police officer with the dog adds the vital ingredient of human judgement, he adds.

This actually makes a lot of sense. Men with machine guns on the Metro freak people out, but many people like dogs, and they wouldn't make our hair stand on end as we are traveling to work or going to a baseball game. DC Metro should start using Beagles to patrol the stations instead of heavily armed men. Hopefully Metro will be spending more time on real security rather than arresting people for talking too loudly on a cell phone or for eating a candy bar in the aftermath of the London bombings.