As a leading global construction company, almost everything Skanska does affects the environment. In the UK the firm works on large projects such as the Channel tunnel rail link and widening of the M1, as well as thousands of smaller ones. It also digs hundreds of holes each day to replace and renew the gas, water, electricity and telephone lines up and down the country.

The company does everything it can to minimise its environmental impact, earning it a positive green score of 81% in our staff survey. To ensure its policies are known and understood from the outset all staff get environmental training when they join and they say it is not only adequate (77%) but also makes them think differently about what they do at home (78%).

Workers receive regular communication on green issues (82%). In 2008, environmental briefings were given to more than 8,000 people including subcontractors. The firm has also developed a sustainability e-learning course for employees.

Workplace signage is a constant reminder to think green (83%) and Skanska's 25 full-time environmental staff also keep employees on message, although employees don't have to look far to see that the firm practices what it preaches. Permanent offices use electricity from renewable sources and the buildings it develops include energy-saving designs such as biomass boilers and lake source heat pumps.

Staff realise that how they do their job has a bearing on the environment (82%) and they are aware of the firm's green policy (89%). A waste assessment is carried out on all projects with a subsequent management plan sent to employees and subcontractors. Waste is segregated on sites and excavated materials are used to make underground floor slabs or used in permanent landscaping.

Saving water is also a priority. At some locations Skanska is recycling water from sinks, showers and baths (grey water) and it is also piloting rainwater recycling in temporary units at a site in London. Efforts to conserve water resulted in a 12% reduction in usage at its main offices last year. In the past two years the firm has spent more than £2.5m on improving its environmental performance. Employees say the firm is serious about its environmental commitments (89%). By 2010, the firm aims to have signed up all subcontractors to its environmental policy, have 50% of company cars emitting less than 130g/km CO2 and to cut waste to landfill from 16.4% to less than 10%. In 2008, all of Skanska's office waste was diverted from landfill.

The firm, which plants trees at Cowdray Park in Sussex to offset business air miles travelled by UK-based staff, is getting better at protecting the environment (92%), say employees. They think green initiatives are worth the money the company has invested in them (90%) and say that Skanska's environmental impact is improving (86%).

It all helps the business climb one place since last year in our Green List rankings.