Regional trading arrangements are a second-best option as they are often accompanied by protectionist measures against countries that are not part of the pact.

No one knows with certainty the impact of no-deal for the simple reason that no developed nation has ever left overnight its preferential trading arrangements in this manner.

The trading arrangements outlined by the prime minster last week represent the worst possible outcome for the big banks.

Economists are expecting a trident of policy themes under the banners of deregulation, renegotiated trading arrangements and tax reform.

High inflation caused by the currency's devaluation has hit consumer spending and uncertainty about trading arrangements has deterred business from investing.