Tomahawks, in response to a query above.
1. The Brits
AFAIK do not need US permission to launch. I seriously doubt the MoD would have bought them with such a string attached.
2. There is GPS and then there is GPS. Depending upon the mod and config of your Tomahawk (and recalling its original design to use preloaded terrain features to arrive at and hit target) I will say with mild confidence that FAA class GPS will get you close enough, at which point the resident maps and map matching function guides the end game target strike.
I won't comment further, for more than OPSEC reasons.
I am a few years out of date on Tomahawk, but my reading on the topic leads me to believe that they've only gotten better, and more flexible, particularly with the new "loiter" mod. No idea which modifications and features have crossed the pond.