National Grid’s domestic transmission system covering England and Wales is linked by an interconnector to the transmission system of France. Although there is sufficient generation in the British transmission system (which includes the Scottish transmission network operated under licence by the Scottish transmission owners) to meet demand, by linking to another country’s transmission system, National Grid can facilitate competition in the wholesale electricity market covering England, Scotland and Wales.

In February 2000, National Grid was awarded the contract to build an interconnector between Tasmania and mainland Australia. This link, the 'Basslink' interconnector, was commissioned in 2006.

In May 2007, National Grid also announced that it would be proceeding with the BritNed interconnector between the UK and the Netherlands. This is a joint venture with Dutch TSO TenneT and is expected to be completed by late 2011.