A Ring of Steel for London's Square Mile

In Europe horrendous incidents have occurred with large trucks used as weapons in cities where people are gathering and celebrating. In medieval times city  walls, moats and watch men protected citizens.
There may be a 21st century approach to these measures in cities like London that have identified their historic “Square Mile” as being under threat of a terrorist attack. The “Square Mile”  is the nerve centre of global financial interests and holds nearly 10 trillion pounds in banking assets. Securing access to this area is the City of London’s responsibility, with powers and laws that have been given to the City since medieval times.
The BBC News reports that upon the recommendations of  MI5 and counter terrorism police  rising street bollards and crash proof steel barricades have been  proposed  to thwart any “hostile vehicle-borne security threat”. This type of barricade was first introduced in the early 1990’s  as a response to the IRA (Irish Republican Army)  bombing of the Baltic Exchange. The Gherkin building now stands on the site of that building.
Manned checkpoints are also going to be reinstituted, something that was phased out after the 1994 IRA ceasefire. It is expected that the 5 million pound (8.2 million Canadian dollar) security steel ring may be in place within five years, providing a band of security around the square mile.