The British pound is 0.45359237 kg, no?
The fixed exchange rate between pounds and kg is obsolete and inappropriate for a modern economy and is the kind of thing BREXIT was supposed to free us from.
It's wonderful that we have different miles and feet for different purposes, and even different exchange rates between them.
Let the Europeans suffer under the yoke of the rigid and procrustean french measurement system. Let freedom of expression flourish!
"Since the revision of the SI on 20 May 2019, we can now compare the gravitational force on an object with an electromagnetic force using a Kibble balance. This allows the kilogram to be defined in term of a fixed numerical value of the Planck constant, a constant which will not change over time."
"A Kibble balance is an electromechanical measuring instrument that measures the weight of a test object very precisely by the electric current and voltage needed to produce a compensating force. It is a metrological instrument that can realize the definition of the kilogram unit of mass based on fundamental constants."
"One important reason for the change is that Big K is not constant. It has lost around 50 micrograms (about the mass of an eyelash) since it was created. But, frustratingly, when Big K loses mass, it's still exactly one kilogram, per the current definition. When Big K changes, everything else has to adjust."
Not sure if this is a joke about weights changing over time or in different places due to gravitational differences - but if you mean mass that was true until fairly recently, the kg is no longer defined by the mass of a specific physical item.