“So we came back and had a discussion as to whether we could do a campaign on that, and spent an interesting afternoon putting it together.” While all staff wore orange underpants with: “Fair trial my arse” written across the front, Mo, the company’s chief inventor and head of manufacturing and production, had created a product for the occasion – a bath bomb from which the faces of the two prisoners float out. “We got into a lot of trouble with that,” says Mark, smiling like a cheeky schoolboy. “The local MP thought it was in extremely bad taste. And they were very cross in Australia and we didn’t even sell it there!

The story sums up the Constantines perfectly. They are ethical entrepreneurs, passionate about their work and the causes they support, but they are no earnest “do-gooding” couple. Everything is done with a smile, a giggle, and a good dollop of irreverence. Take the comic book style Lush product names: Mange too massage bars, or Sonic Death Monkey shower gel.

But ingredients are vegetarian, the majority of products have no preservatives at all, nothing is tested on animals and packaging avoided where possible. The shop has a ‘charity pot,’ from which all proceeds (less VAT) go to the shop’s chosen charity of the month. That can range from, “very serious and earnest things in Africa to paying for the [Terminal 5 protest] banners that came down the Houses of Parliament,” says Mark, who has just come back from London on a PR trip in support of the Green candidate for Mayor of London.

The Lush core team has been together for over 25 years, having lived through the rise and fall of the Constantine’s earlier venture, Cosmetics to Go. This time it is a different story. Lush was formed in 1994 and now has over 520 stores in 44 countries. Turnover for the year ended June 2007 was £144m. This is a respectable business with global presence.

It’s been listed in the Sunday Times ‘Top 100 companies to work for’ rankings for the last seven years, although Mark plays that particular accolade down. “There’s no secret, it’s not that we’re great, it’s just that the other companies are crap. I think the way we work should be the average, and there’s still an awful lot above that that we’d like to achieve.”

Part of the appeal is the vibrancy of the business. As Mark says, there isn’t a lot of “paraphernalia”. In the UK for example, there are no area managers, just one team running retail and another running manufacturing. Fifteen per cent of Lush product is changed every year – it used to be 30 per cent and there are plans to get it back up to that figure.“ It’s more fun that way.” says Mo.

The guys in production always like something new. We don’t hold a lot of stock, we buy in fresh product, and have a rapid turnover of stuff which makes the whole thing quite vibrant.” Mark hopes that his communication policy also deters rigid hierarchical structures.

A DVD is sent to each employee every quarter, and he would like to think that, “sometimes someone goes into their manager and says ‘why do we never do that, we’re meant to be doing this.’ It means that no-one can act autocratically.”

Or, charmingly, “When a woodpecker drums on a tree, what you hear is not necessarily the bird drumming, it’s the echo of that drumming coming off every other tree. You don’t have to have a hierarchy for a message to pass down – it can pass down 101 ways.”

The one thing vexing the Constantines is succession planning – how to achieve the successful transition of the business to people they can entrust with its ideals and values.

Mark and Mo were horrified when Anita Roddick sold the Body Shop to L’Oreal, seeing it as a betrayal of everything that the company had stood for, and that they had played a part in creating, having been the Body Shop’s main suppliers for years pre-Lush. The situation was aggravated by Roddick’s rejection of their own offer to buy the company, which soured a formerly strong friendship.

They are determined that they will not be put in the same position and are starting to consider options now. They would like staff to have shares in the company, but are frightened of setting up anything with too rigid a structure, creating something more akin to “Grace Brothers”. In any event, “for us to go down that route, Mark has to die and I have to lose my marbles.

We’re not quite there yet,” says Mo. A preferred option would be to split the ownership between family, staff and the management team. But the best way of achieving that, without again, the spectre of a controlling hand reaching out from beyond the grave, is not yet clear.

Of greater immediacy is their drive to act as role models for future generations of ethical businesses. Given big businesses’ desire to “greenwash” themselves, ethical companies such as Lush sell for four to five times sales, according to Mark, which is too tempting for most. Lush aims to lead by example. “There is a need for leadership for ethical companies and I think Body Shop provided a lot of that.

It’s quite difficult to be constantly mouthing off, and poking people with sticks. We had chosen not to do it while they were, but someone needs to be out there aggravating everyone,” he says smiling. “People take it for granted now, but 20-30 years ago, Anita had the balls to push out there. I would never have taken it as far as I do now or she did then.” He pauses. “I’ve had to come to terms with how influential she was in my life.”

Now he’s in reflective mode, Mark ends by summarising the two things he has learnt over time: “Respect money. I didn’t. I was far too cavalier with Cosmetics to Go. Secondly, respect your luck. I’m fortunate to be able to do this stuff, so do it with that knowledge. There are so many people who’d love to be in this position, it would be almost as if I was laughing at them if I didn’t treat my position with respect.”