Milton Keynes shopping mall, thecentre:mk, has bags of ideas when it comes to being green. The latest is Big Hanna — a hungry addition to the mall which turns leftover food, including meat, into compost. As well as boosting its blooms with its fertile produce, Big Hanna also eats away at thecentre:mk's total waste production, helping it divert 100% of its rubbish from landfill.

Employees report that environmental targets tend to be achieved — the 91% positive green score they give the company beats every other firm on the list. They appreciate the efforts to reduce waste and don't think the organisation produces too much (81%, a top five score).

In October last year, thecentre:mk earned ISO 14001 certification. Staff know what this means (89%) and they are aware of the firm's environmental policy (93%). Both are top 10 scores. Rather than opt for carbon offsetting, thecentre:mk is doing all it can to reduce its 5,765 tons of carbon emissions. For instance, used cooking oil from the retailers in the shopping centre is collected and converted to biodiesel, which runs its vehicles. Employees feel the organisation always does what is best for the environment (88%) and doesn't merely plump for the cheapest option (87%).

About half of the energy used at the shopping centre is bought on a green tariff, and up to 20% is generated on-site by a new biodiesel plant. Staff think thecentre:mk's impact on the environment is improving (93%) and are aware of the implications of the work they do (88%).

An extensive rainwater harvesting system is planned, with enough capacity to offset the water used in the male customer toilets. People are kept abreast of new initiatives through an employee newsletter, environmental e-mails and special events to raise awareness. There are also plenty of signs around the shopping centre (87%), which has a green reputation among the friends and family of staff (85%).

A 95% score shows that employees know exactly what waste goes where at work and fully understand the mall's carbon footprint (81%). New starters are given environmental training, which is kept up to date with refresher courses. Last year, £127,515 was spent on green initiatives. Employees say this is money well spent (92%). They are happy the company does a lot for the environment (a 95% score ranks it third overall), and are satisfied that its commitments are not simply for the sake of good publicity (73%).