We have reasonable designs for almost all weapon categories, except maybe for airplanes, with the latest being the Eurofighter which is by now a bit dated. Regarding Tanks, the German Leopard is as far as I am aware a fine piece of engineering as well as the belgian FN-SCAR. However we lack the ammo capabilities (especially when it comes to artillery shells) to ever have hope of winning a protracted war (or simply keeping Ukraine alive). (also, quick side note, France also spends a great deal of money maintaining their own nuclear arsenal and weapons delivery system, which kinda makes the UK seem a bit puny with their dependence of the US for weapon delivery)