For the bosses of Britain’s companies, the ticket to green credibility comes only if the staff are included on the journey.

That is the conclusion from two years of The Sunday Times Green List, the benchmark against which businesses can test their green credentials. Organisations can register for the 2010 contest from today.

The contest not only measures efforts to cut the corporate carbon footprint, it also seeks employees’ views on how green their company is.

The top 60 green companies of 2009 ranged from blue-chip multinationals such as BT and Tesco to construction companies with a high environmental impact, including Willmott Dixon, Carillion and Skanska — and not to forget small marketing businesses such as the current champion, Forster, with only 51 staff.

They may differ in size and environmental impact, but what they share is a genuine commitment to putting green issues high up the agenda. They have the strategies and staff input to make it happen.

Our methodology allows companies to compete on a level playing field. Our top 20 this year featured eight companies with fewer than 250 employees, six mid-sized organisations and six with more than 5,000 staff. Eight had an environmental impact classified as low, six were medium and six high.

Will Ullstein, director of innovation at Munro Global, a market-research group and a partner in compiling the Green List, expects competition for a place on the 2010 list to be heated. “Organisations are increasingly understanding and reaping the benefits of running green operations. Media attention is propelling environmental issues up the agenda, and the countdown to the Copenhagen climate-change conference will only focus attention further,” he said.

With the benefit of two years’ data, companies can see the key trends that lead to success on the Green List. Genuine leadership on all things green is vital, as is getting the message across to the workforce.

Of the 52 questions on this year’s employee questionnaire, 13 test employees’ feelings about their bosses’ green credentials. Employees rate from “strongly agree” to “strongly disagree” their response to statements such as:

- My boss is open to suggestions for environmental improvements;

- My boss encourages me to recycle at work;

- My boss expects me to save the environment while he/she drives a gas-guzzling company car.

For companies, there is a close relationship between achieving high scores on the My Boss questions and doing well in the employee survey overall.

Sarah Davidson, technical director at Bureau Veritas, the environmental consultancy and our other partner in producing the Green List, said leadership is the place where the employer and staff surveys meet.

“This is where we get the connection between the employer and the employee responses,” said Davidson. “Leading by example in senior management is the key to linking the corporate programmes with the performance of the general workforce in the employee survey.”

Rick Willmott, chief executive of Willmott Dixon, the construction company that finished third in 2009, knows he has to lead from the front. “You have to set the agenda. You have to nail your colours to the mast,” he said.

Even though the building trade has by its nature a high environmental impact, Willmott thinks entrants should not be deterred.

“If we can make differences, they tend to be big differences. So that’s the very positive upside for us — we only have to flex a few things very gradually and gently and we can make some significant inroads,” he said.

Analysis of 2009’s results shows that about half of Willmott Dixon’s staff fell into the “pragmatic green” category of employee, one of four broad clusters of staff identified from the responses of 20,000 employees. The other categories were “true green”, “sceptical green” and “least green”.

Most staff in small organisations (38.7%) could be classed as “true green”. In mid-sized firms most were “pragmatic green” (33.3%), while in large businesses most fell into the “sceptical green” category (33.8%).

Where employees can make a difference, there is a green dividend. Among statements where strong agreement is closely correlated with a high ranking are knowing where to put waste for recycling at work, being kept informed of company environmental policies and having a boss open to suggestions for making environmental improvements.

Jilly Forster, chief executive of the 2009 winner, said: “Once you find there’s engagement, you start having people coming up with their own ideas.”

Davidson said: “It’s the staff on the shop floor or at the construction site or in the factory who probably have the greatest influence over the environmental impact of the organisation. So getting them engaged is key. It’s never one fantastic light-bulb moment from the top; it’s lots of gradual changes generally that make a difference.”