Nearly 6,000 companies are now compliant with the Energy Savings Opportunity Scheme (ESOS), according to the Environment Agency.

A further 1,000 businesses were on course to become compliant as the deadline passed on 29 January.

But a further 3,000 firms are not yet compliant, the regulator warned.

Under the European Union Energy Efficiency Directive, any business with more than 250 staff, annual turnover in excess of €50 million (£39m) or a balance sheet worth more than €43m must comply with the ESOS.

Enforcement notices

An Environment Agency spokesman said: “It will take some time to match all of the notifications to the expected participant groups and verify whether the remaining organisations do in fact qualify.

“Our focus is on bringing organisations into compliance with ESOS and we will start contacting those organisations that have not yet complied this month.

“We will normally use enforcement notices to bring organisations into compliance and only issue civil penalties in the most serious cases.”

> Download the agency's ESOS guidelines