Here is an extra interesting Victorinox knife and it got an inlay for BP that should be British Petrolium.
The functions and stamp is 1961-1970
and the feel for me is mid-1960s. It is a 84mm category.
On the wiki page for BP you can find much interesting information that goes well with a collector hobby. Advertising knives can be very
interesting because you can cross date the knife and advert. Sometimes you can be lucky to find dates used on advertising knives that may help you to become better in dating knives.
It seems to be
that the inlay is made of nickel-silver with quality. The quality on the 84mm knife itself is very good. They are durable and the springs are fully operational. It must have given a very solid impression to receive this knife back then. It is Victoria stamped.