British National Electricity Supply
- Country: United Kingdom
- Type: Commercial
- Website: www2.nationalgrid.com
- Update: 05-01
National Grid Transco is the largest energy and utility company in the United Kingdom. It was formed on April 27, 2002, by the merger of National Grid, a British energy provider with international energy transportation, and Lattice, a natural gas transporter, which was part of British Gas and operated a natural gas transportation system.