Since launching Plan A five years ago, we've set about transforming our business to reduce greenhouse gas emissions. By setting ambitious targets and focusing on every store, every truck and every office, we've managed to cut our carbon footprint even while the business has grown.

So how did we reduce our carbon emissions? Five years ago, our emissions added up to the equivalent of 730,000 tonnes of CO2 per year - that's the equivalent of the energy use of all the homes in Newcastle. In 2012, that figure has fallen by 22% in spite of the business growing - effectively our footprint is 35% smaller than it would have been without Plan A. We've achieved this by being scrupulous about monitoring our energy use; giving each of our stores individual targets to achieve; pioneering new technologies like our groundbreaking fridges and investing in new equipment in our stores and offices; from air conditioning units to fuel efficient, aerodynamic teardrop-shaped truck trailers.

Inevitably, a business the size of M&S will always have some carbon emissions. To achieve our goal of becoming carbon neutral, we've been buying carbon offsets to balance these out. Not only does this help tackle climate change, it provides an extra financial incentive for us to keep cutting carbon directly - the smaller our footprint, the less we'll need to spend on offsets.

In order to count towards our carbon neutrality, offset projects must be certified as leading to carbon savings that wouldn't have happened if the offsets hadn't been purchased. You can read all about them here.

Our responsibilities don't stop there though. As a retailer, we can be carbon neutral, but the products we make have their own, much larger footprint, which includes everything from the tractor on the farm where our fruit and veg are grown, to a customer using their washer-dryer to launder M&S clothes. To help mitigate this footprint as much as we can, we go out of our way to share our carbon-cutting expertise with our suppliers, via our Supplier Exchange programme. We've also set up eco factories around the world.

We want to help our customers cut carbon too - especially when it comes to consuming and disposing of M&S products - so we've launched initiatives like our Wash At 30 campaign, and rewritten the advice on food packaging to help consumers reduce food waste.

Climate change is a big and complex problem. We believe that we'll only solve it if we all - M&S, our customers and our suppliers - work together. Becoming the UK's first major carbon neutral retailer seems like a good start.