Class D vs Clock Position

[malecontrol]

A Canadian instructor of mine once told me a TWR controller cannot give clock positions while giving traffic information to aircraft in a class D airspace. He taught us to pass traffic info as traffic on your left or right. Is it just rule in Canada or is it an ICAO rule? If so what is the reason for that?

[Spitoon]

I'm not aware of a rule that says this but it's probably a idea - it's difficult to tell the relative orientation of two aircraft from the TWR.

Even if you're using a radar display you're going to have to make some assumptions about the direction an aircraft is pointing it the traffic is VFR.