See the definition of a micro business, as outlined by the energy regulator Ofgem
What’s a micro business?
You’re a micro business if
You use less than 100,000 kWh of electricity a year OR
You use less than 293,000 kWh of gas a year OR
You have fewer than 10 employees (or their full-time equivalent) and your yearly turnover, or yearly balance sheet, is not more than two million Euros
The consumption threshold applies to the fuel being supplied