In May 2012, I was recruited to join the launch event for Yes Scotland - the eagerly anticipated campaign for a Yes vote at the referendum on Scottish independence.

I was approached as chief executive of Friends of the Earth Scotland and quickly found myself one of a hastily assembled group of actors and activists, socialists and singers sharing the stage at the Cineworld complex in Edinburgh's Fountainbridge - an uneasy mix of Holyrood and Hollywood which seemed to have been put together with the aim of having something for (almost) everyone.

While the political Greens were represented by Patrick Harvie MSP, they hadn't yet taken the decision to fully or formally engage with the Yes campaign, so my background as an environmental campaigner allowed me to be brought in to add a much-needed eco-veneer to proceedings and help demonstrate the alleged breadth of support for Scottish independence. Back then, I was keen to point out that you don't have to vote SNP or be a nationalist to support independence - something the Yes campaign has since well established.

Over the last 15 years, I've seen the significant benefits devolution has delivered for Scotland, and I've been able to influence many of the positive changes that have taken place in that time. But there's only so much that can be achieved within the current system and change for the better is being stalled by the limitations of the current devolution settlement. If the green principles of sustainability, equality, subsidiarity and democracy, which I support and espouse, are to be fully realised, Scotland needs to take control of all the policies and activities that affect these things.

A few months after the launch event, I joined the staff team at Yes Scotland - the short-life limited company set up to promote a Yes vote. In those early days, considerable effort was put in to making Yes Scotland look like it was more than "just the SNP". I remember hastily cutting and pasting "alternative views" from greens, socialists and other non-SNP types on to the Yes Scotland website in an attempt to demonstrate the organisation's diversity while journalists sat on the other side of a glass wall at Yes HQ demanding an audit of the political affiliations of the organisation's staff and asking difficult questions about the backgrounds of funders and activists. Back then, it was a challenge to find a voice that wasn't pro-oil or pro-SNP on the Yes Scotland website.

It's no surprise that the early adopters of the Yes campaign - the constitutional missionaries - were almost exclusively active SNP members - those for whom independence was already a significant issue. The job of the communities team I joined was to bring others on board and broaden out both the Yes Scotland organisation and the wider Yes campaign to be more than just the SNP.

I'm proud to say that we were very successful in doing so. Within the wider Yes campaign, party politics have been set aside by many and unlikely new alliances and friendships have been formed, with the inevitable cross-fertilisation and hybridisation that occurs when people of party politics stop attacking each other for a while and actually work together.

The wider Yes campaign has become a movement of the people, become cross-party and non-party, with those without party affiliation now vastly outnumbering those with it. It has moved away from political identities to become something more diverse and more convincing than the SNP, and in doing so has left Yes Scotland behind. In many ways, the Yes Scotland organisation is now redundant.

In my opinion, this is just as well, as that organisation has become little more than an SNP front in recent months, which is ironic given the amount of effort that was put into fighting that perception in the early days. It's also depressing and counter-productive, because now that the wider Yes campaign is mature and self-sustaining, it contains within its mass an impressive range of reasons for supporting independence and a variety of visions of what Scottish independence might look like. So many of these are more interesting, compelling and convincing, more radical and more reasonable, than those set out in the SNP's White Paper, but the SNP's vision of independence is the only one we're hearing from Yes Scotland once again.

Many will be surprised to learn that Yes Scotland no longer produces its own campaign resources. The Yes-branded newspapers currently dropping through letter boxes are written and produced by the SNP. The only clue to this is the tiny imprint hidden on an inside page. The Yes billboards that have appeared in every town and city in recent weeks were devised by a creative team engaged by the SNP without any input from what remains of the Yes Scotland team, which often only sees these resources well after they've been distributed to SNP members and activists.

The most recent Yes newspaper featured a Scottish Green Party councillor in its centre spread, yet made no mention of the launch of "Green Yes", the Scottish Green Party's distinct, policy-driven campaign for an independent Scotland which had been launched just a short time beforehand. Instead, the image was used to promote the policies in the SNP's White Paper, many of which are actively opposed by the Scottish Greens.

A similarly disingenuous approach was taken with a number of Labour Party activists from the left-of-centre Radical Independence Campaign, and this has led to increasing tensions among the partners represented on Yes Scotland's powerless advisory board. In recent months, the Scottish Green Party has quietly created distance between itself and this SNP-led Yes Scotland while remaining an active part of the wider Yes campaign, choosing instead to focus its referendum activity on promoting its own vision of independence through Green Yes.

While I personally think the campaign for a Yes vote would be better served by a Yes Scotland organisation that was independent of the SNP - one that was able to disseminate a broader and more varied message and better represent all of the constituent parts of the wider Yes campaign - I do understand why the SNP has taken the decision to recapture Yes Scotland.

After 80 years of campaigning for independence, it must have been difficult for the SNP to hand over the job to a bunch of Johnnies-come-lately. I experienced this first-hand at an SNP conference in Perth where the resentment of some the party's more diehard supporters led them to tell me to "leave the real politics to them and get back to my tree-hugging".

But the SNP needed a separate entity to do what it couldn't do - a stalking horse to engage those from other political backgrounds, those with no political interest, or those for whom the SNP and Alex Salmond are a turn-off. Now that's been achieved, it's unsurprising that the SNP has retaken control, but it doesn't help the case for a Yes vote.

Unfortunately, the SNP also had little choice but to step in, as the Yes Scotland organisation was dysfunctional from the start and continues to underwhelm due to a lack leadership, strategy and resource.

I survived 16 months working at Yes Scotland, during which time I witnessed more roaring tantrums, faux resignations, bad-tempered walk-outs, pointless meetings, chaotic activities and last-minute panics than in the rest of my 25 working years put together. It's just as well that the wider Yes campaign has been such a runaway success.

Looking back, however, it wasn't all Yes Scotland's fault. The decision to launch the Yes campaign early was taken to make headway on an unprepared opposition and to lock in the word "Yes" before it could be co-opted by the other side. At the time of the launch, Yes Scotland had no staff or board and was being run by two seconded SNP special advisers (SPADs) from a serviced office in Edinburgh. By the time I and the other directors were recruited in September 2012, Yes Scotland was on the back foot and playing catch-up. A summer of inaction had failed to capitalise on the momentum created by the launch and this had left supporters and activists frustrated

and underwhelmed, turning them against the organisation from the start.

Worse still, those SNP fixers involved in the design and establishment of Yes Scotland had no experience of running a campaigning organisation and it was inexplicably set up without an experienced campaign manager to provide strategic direction and leadership or a fundraiser to ensure that the organisation was crowd-funded through its grass-roots support. This was akin to buying a ferryboat to take lots of people on a journey but not bothering to recruit a captain or buy a compass or fuel.

Those who set up Yes Scotland had assumed that the money would just follow, but this never happened. By the end of last year, it had become impossible for the communities team to fund even the most basic activity due to a lack of cash, and while we were able to crowd-source some funds, it was never going to be enough to fund a team of overpaid directors and consultants and a fancy city-centre office. Something had to give, and now Yes HQ on Glasgow's Hope Street is largely staffed by the "three Ss" - a small group of worthy Survivors, some ultra-loyal Secondees from SNP HQ, and a number of random Stooges brought in to make up the numbers.

The narrowing of the polls and the steady progression of undecideds towards a Yes vote in recent weeks has been in spite of Yes Scotland, not because of it. It has had more to do with the relentless negativity of the No campaign and the unhelpful actions of its members, turning people away from No, and it has been because of the enormous amount of under-the-radar activity that takes place each day within the wider Yes campaign, where so many of the best ambassadors for Scottish independence have had no contact with Yes Scotland at all.

Instead, they've been convinced or recruited by friends, family or workmates through simple conversations and have decided to start conversations of their own. That peer-to-peer influence is the Yes campaign's major strength, with voters hearing the positive case for independence from people they know and trust, in situations in which they feel comfortable, in a language they understand and using arguments that are relevant to them. This is happening at school gates, in works canteens, in pubs and through social media, as well as on doorsteps across Scotland, and this activity of the wider Yes campaign is what will win a Yes vote on September 18.

When the history of the Yes campaign is written up post-referendum, it will likely state that the campaign was won by the SNP. If that does become the case, then it will do a massive disservice to those involved in the wider, bigger, better Yes campaign. Whatever is written, Yes Scotland will be forgotten.