[adrian_b]

Yes, but while the moat surrounding the US embassy in London will not deter drones, it will prevent any car from reaching the proximity of the building.

A car can carry a much higher explosive load than even a lot of cheap drones. Moreover, in London a car will become suspicious only when it is already close to the embassy, and there is little time available to react, but drones should be detected much earlier.

[inglor_cz]

"drones should be detected much earlier"

Not if you follow in the steps of Ukrainian "Operation Spider Web", which concealed the explosive drones into a double roof of a truck and when the truck got into the proximity of the target, the roof opened and everything flew out at once.

Granted, in the case of an embassy in London, you probably couldn't get a semi there, maximally a modest truck, but that should be enough for some damage.

[cucumber3732842]

You don't even need to follow Ukraine.

The IRA bombed 10-downing street out of a van. All they did was do some math, mount the mortar at the right angle, have a hole in the roof and park where the math said they ought to for that firing angle.

Nevermind the fact that civilian surveyors, work estimators, etc, etc, constantly just launch (smaller) drones out of the sunroof of their cars.