The accord was set up in order to facilitate the cross-border flow of travellers and goods, while co-ordinating enforcement efforts in the two countries.

Firms increasingly operate through international business networks, generating cross-border flows of information, people, skills and finance.

Yet the impact of a disruption of cross-border flows of goods, services, capital and labour can be predicted.

The absence of currency risks within the euro area created more competitive financial markets and facilitated larger cross-border flows of capital.

One sign of this was a decline in cross-border flows between euro-area banks.