New Royal Baby's Security Will Be 'Discreet,' Expert Says

— -- Security surrounding the birth of the next royal baby is likely to be high, even if it goes mostly unnoticed.

"It'll be done in the usual British way: discreet," Dai Davies, former head of London's Metropolitan Police, which provides protection for the royal family, told ABC News.

"It's a fairly smooth machine," Davies said, explaining that there's a well-tried system in place. "His father had it, his father had it before him and so on."

The Palace never comments on security matters around the royal family.

But Davies explained that the family is actually protected by a special department of Scotland Yard called the Royal Protection Command. Between 450 and 500 officers serve in the command and each royal is partnered with a team, Davies said.

The same team that has been looking after Prince William, Kate Middleton and baby George will likely take the lead protecting the newest royal, Davies speculated.

Even as security in Britain is at its highest level ever amid terrorist attacks earlier this year in France and Belgium, Davies said the biggest concerns about safety come from those who are mentally ill or fixated on the royals.

"That's where the core threats come from," he said.

Of course, the command is on the lookout for terrorists as well. Already there are plenty of plainclothes officers doing reconnaissance before Middleton goes into labor, Davies said.

The Duchess is expected to give birth at the same hospital where George was born, St. Mary's in London. St. Mary's is also where Middleton's husband, Prince William, and his brother, Prince Harry, were born.

Notices have already been posted outside the hospital, forbidding any parking 24 hours a day from April 15 through the 30th. Middleton is expected to give birth during that time.

"Watching the watchers is a key factor," Davies said. "Contingency planning it's called."

He added, "You think the impossible, then you think it again."

After the birth, the family will likely head immediately to Kensington Palace in London, where they'll spend the first couple of days with their new baby, royal commentator Victoria Murphy told ABC News recently.

"After that the intention is for them to leave and to go to their country home of Anmer Hall," Murphy said of their estate in Norfolk, England. "And really that is where they consider to be their home now, where they feel most comfortable and where they will spend the next few weeks."

Roya Nikkhah, a royal family commentator and writer, explained that the country home has everything the family of four needs in one secure place.

"There's a huge amount of private space there," Nikkhah told ABC News recently. "There's an enormous garden. There's tennis, there's swimming but all in one place. They don't have to get protection officers to take them from one bit to the other as they do in London."

Added Nikkhah, "It's a kind of completely enclosed childhood for Prince George and his new brother or sister that's about to arrive. And I think that's what William and Kate, particularly William, wants for his children. He wants to have that incredibly normal life that's completely private, that's away from the spotlight."