The government’s advanced meter roll-out scheme, which began in 2009, requires suppliers to fit 155,000 business customers with, and supply electricity through advanced electricity meters by April 2014.

However, assessments reveal that only 75% roll out was complete in electricity, compared to 86% complete in gas, Ofgem said.

British Gas, E.ON and npower had the lowest completion rate of installing advanced electricity meters for business customers.Over half of the 40,000 advanced electricity meters are still due to be installed.

Ofgem markets division senior partner Rachel Fletcher said: "We are disappointed in the overall performance of the majority of suppliers concerning the roll-out of advanced meters to business customers.

"These new meters offer real benefits to customers including saving money through reduced energy consumption and ending estimated billing."

"All suppliers can and must learn the lessons from the roll-out of meters for business customers and apply them to the domestic smart meter roll-out."

The investigations were opened into three companies which did not roll out advanced meters to all its eligible customers.