Back then every component of a battleship, the most powerful and advanced weapon of the time could be built independently by Britain, France, Germany, Italy, USA, Japan etc. Today, there are very few weapons systems that do not depend on allied countries for a critical component. E.g. it is quite well known that Britain's nuclear powered subs use US reactors and US missiles, but even the steel plate for the hull is likely sourced from another country as there is only one steelworks left in the UK which probably is not able to produce the right alloy in the desired thicknesses. In fact, industry in the UK has declined to the extent that we could not independantly produce a WW1 era battleship any more without a vast restructuring of the economy which would take decades.