Carts filled with plastic water bottles. Credit: _molins/Flickr. Some rights reserved.Charlie Holland's post on Facebook about a brilliant innovation to London Waterloo station was a surprising hit. The post and his photos, shot on the concourse on a phone camera, got some 3.5k shares and over a thousand likes, too.

The innovation was designed to make a dent in the huge number of plastic bottles bought by making it easier for people to refill their bottles while out and about. See where I'm going with this? It's a tap. A sandwich shop called Pure installed a public-access tap for drinkable water outside its doors in the hope people won't need to buy a bottle if they already have an empty one on them.

A water bottle has become an unmissable fourth item in the 'idiot checklist' I do before leaving the house. It used to just be keys, phone, wallet, but the cost of shelling out for cans of Coke and carry-out coffees has forced me to be a bit thriftier.

Naturally this means I'm pleased to see Pure has made it easier for all of us to break pointless spending habits, and challenge the instinct to shell out for San Pellegrino. The country's busiest station last year, Waterloo was a gateway for some 99m journeys in the last annual report on travel stats, and nowadays with people come plastic water bottles.

But what's more impressive, surely, is the fact that this is not Waterloo's only tap. At the last count, 28 places in Waterloo sell fresh food and drinks, and presumably every single one of them would refill a water bottle, if asked.

71 per cent of people admitted to feeling uncomfortable when asking for free tap waterStupid as it sounds, I still feel shy, marching up to a counter and asking the server to fill a water bottle when I'm not a customer. I'm only admitting to this because I discovered that in a recent survey, 71 per cent of people admitted to feeling uncomfortable when asking for free tap water. A surprising 30 percent said they would still feel awkward asking for a free refill even if they had bought other food or drinks.

I'm proud to say I'm not a total disgrace when it comes to the environment: I recycle (and I wash cans before throwing them in the green bin). I sometimes pick up litter on my way home (a fairly gross habit I got off my mum). And I try my darnedest not to use tin foil (since Ray Mears pointed out it basically never rots). But evidently I've still got a fair way to go before I can, say, become a zero-waste blogger.

We've seen some great breakthroughs recently that will help cut down on how much plastic we use - the increase in the use of recycled materials, the plastic bag charge, the pledge to ban microbeads. Support for these changes is strong and widespread: the challenge is simple, and people want to make a difference.

Policy and inventions aside, though, the tap in Waterloo is a gentle reminder of how the best changes work with our nature, rather than against it. Thumbs up for making it easy to do the right thing.