Defence constitutes a rather atypical industrial sector. Due to the sensitive nature of its products, it has long been strictly protected by states and ‘placed outside the bounds of free-market economy’. Countries with a relevant industrial base have traditionally sought self-sufficiency in arms production for national security. States’ control over their domestic industry has frequently slowed or even hindered attempts at cross-border European cooperation. This has ultimately resulted in a significant fragmentation of the European defence industry.