Less than one in ten small technology companies assess their CO2 emissions, according to the Carbon Trust.

Ninety-four per cent of survey respondents said they do not track their carbon footprint, citing lack of expertise as the key barrier.

But small and medium enterprises (SMEs) do have a signficant environmental impact, according to Carbon Trust chief operating officer Michael Rea.

"SMEs account for around 20 per cent of the country’s overall emissions so it is essential they are supported to act on climate change," he said.

The Carbon Trust is launching a campaign to urge smaller businesses to apply for an interest-free loan to replace or upgrade existing equipment to more energy-efficient versions.