THERE is a charming, seemingly random, video on YouTube of Paul McCartney demonstrating how to make mashed potatoes. It's a recipe from Linda McCartney's On Tour book (he is following the instructions from his own well-thumbed copy), and there is something endearing about the way he shows you Linda's tip on how to chop an onion, as he hacks away with the knife in a way no professional chef would.
He is no Jamie Oliver. Obviously, Sir Paul has other talents, and his guide to making mash the Macca way, a video he made as the president of the UK's Vegetarian Society, is just a bit of fun -- the perfect accompaniment to a couple of Linda's vegetarian sausages.
Food was a key part of Paul and Linda's relationship, and when they went vegetarian in the Seventies, it was a spontaneous and joint decision, he says. "We were on the farm and we saw lambs gambolling and we were eating leg of lamb. So it was a compassionate thing. That seems to be the least important thing to people these days. It seems to have gone right out of the window, unfortunately."
Linda's food still brings the family together. They are actively involved in Linda McCartney Foods, which recently had a bit of a dust-off and a rebranding. They all taste and approve new recipes, and I imagine their freezers are well stocked with Linda's burgers and sausages. It is important to them; it is their way of keeping her legacy alive. So when Sir Paul decided to launch the campaign Meat Free Monday -- the aim of which is to persuade people to go veggie once a week to reduce greenhouse gas emissions from livestock -- it was the perfect opportunity to get together for a rare public group hug.
As he muses over a suitable recipe for another cookery video to promote the campaign, he remembers one of his father's favourite recipes: "Pea sandwiches. I remember my dad making one for John once." His daughters -- Mary, the photographer, and Stella, the fashion designer -- groan. "It has to be Mum's lasagne," Mary says. We are in a leafy private garden in Notting Hill, at the back of the Portobello Hotel where, legend has it, Kate Moss took a champagne bath with Johnny Depp. Grand west London villas overlook the garden.
A small girl in a school boater is peeping out of her window, watching one of the most famous men in the world being photographed. Sir Paul waves at her cheerily, and she disappears. While Mary prepares to take the photographs, Sir Paul takes a tiny mouth organ from his pocket and plays as Stella, wearing a vintage powder-blue dress, her high heels making her long legs look even longer, sings along.
"This is why Bob Dylan wants to write songs with you," she laughs. It's a family joke. Despite news reports that the two musicians are about to record together, Sir Paul tells me later that the rumour is unfounded. "No, that's a newspaper thing. He just said some very complimentary things about me in some interviews, and I love him. I think he's a great poet and writer, so I've always admired him. I don't rule it out and I admire him. But we're not the kind of people who would ring each other up."
Mary, dressed in a kimono-style top, has her mother's angular elegance. She takes her place in the picture, arranges her father's hair, which is blowing in the wind, and presses the shutter. The McCartneys are famously vegetarian, but Stella says that for the sake of this particular debate she wishes they weren't -- this is not an evangelical mission to make the world veggie but an attempt to slow climate change.
"It's an environmental conversation, not a vegetarian one," Stella says. "It's OK to just give up meat for one day, it doesn't make you a vegetarian, it doesn't make you a cranky, hemp-wearing pot-smoker, it doesn't make you the kind of person you don't want to be."
Sir Paul read about the campaign in America and decided he needed to get involved. Meatout Mondays have been promoted by the American charity Farm (Farm Animal Rights Movement) since 1985, and the Meat Free Mondays campaign was set up in Australia by a health food company, Sanitarium, in 2005.
Cynics might say that Paul McCartney's campaign is a marketing strategy to sell more of Linda's frozen foods -- veggie bangers and mash is a great quick and healthy Monday supper -- but despite the battering that the McCartney investment portfolio is reported to have taken of late, he is hardly short of money. As he says, he doesn't need to be here promoting this cause. And Stella, who is in multi-tasking overdrive, editing a photo shoot in between having her picture taken, certainly doesn't. But he is here, and part of Paul McCartney's charm is the fact that he is 100 per cent believable.
Over the past year, he has been writing letters to celebrities and chefs, talking to schools and galvanising support from as many people as he can, including Woody Harrelson, Doris Day and Ricky Gervais. A few weeks ago, he held a press conference to launch the campaign at Oliver Peyton's London restaurant Inn the Park. Peyton, a fully fledged bone marrow-sucking carnivore, has agreed to promote meat-free dishes every Monday at the restaurant.
The musician Moby, a vegan for 22 years, was there. Yoko Ono turned up, looking suitably eccentric in a jaunty naval outfit, her Meat Free Monday badge pinned alongside another that said simply, Imagine Peace. She chatted to Sir Paul's son, James, also a musician, as they tucked into Linda McCartney burgers and hotdogs. The campaign has some weighty research behind it, not least from the United Nations. "Dad got the report," says Mary, who is softly spoken but has a cool air of authority about her. "You were sent the report weren't you?" She looks at her father, who is quietly whistling to himself.
He is a great advertisement for a vegetarian diet, looking far more youthful than his 67 years. "Yeah, Livestock's Long Shadow, it was called. The UN, who are our appointed global watchdog, said, 'Hey, cattle rearing is more harmful than all transport'. That is the statistic I thought was shocking, because until then I thought it was aeroplanes, cars and trucks..." According to the 2006 report, livestock is responsible for 18 per cent of the world's greenhouse gas emissions, which is indeed a bigger share than that of transport, which accounts for 13 per cent.
"We're not talking about just a few cows, we're talking billions," Sir Paul says. "I took a drive from Santa Fe down to El Paso, and you go past about 15-20 miles of cattle and it's the same cow -- it's a brown and white cow. There are billions of them! And that's where it hits home. That's where the methane's coming from, not just a couple of cows on a farm. It's not just Daisy and Buttercup any more."
It seems that environmentalists and the UN Food and Agriculture Organisation have come to the same conclusion as the McCartneys: that rearing billions of cows to make beef burgers is not a good idea. It's the first time not eating meat is being promoted by scientists -- "traditional eaters", as Sir Paul calls them, not vegetarians with a vested interest. For Stella and Mary, following their father's lead is perfectly natural. Linda would certainly have been there, waving her placard. She was talking about the relationship between food and the environment long before the UN decided to act. "Ideally, yes, be vegetarian," Mary says. "But if not, just reduce your meat intake."
Listening to them running through the arguments and the statistics, you feel this is a typical discussion that would happen over a family nut roast. Occasionally, they talk over each other and finish each other's sentences.
"It can be so overwhelming," Stella admits. "You can feel so, 'Oh God, but I've got to get that plane to there and I've got to drive my car with my three kids to here'. You are led to believe that transport is the main problem, but actually it's diet. To be honest, we could sit and bang on about it..."
Sir Paul: "... but we don't want to bang on, we don't want to say to you, 'Look, you have to go veggie.' The idea is that it's for the environment, for your children's future: would you consider just one day a week changing your habits? And then if you decide to do two days, three, four, then so much the better, it would have a huge impact."
Stella: "If everyone gave it up on a Monday, it would be more effective than everyone stopping driving their car on a Monday. We are not perfect. It's so important to get that across because it's like, 'Oh, those bloody Maccas, talking again about not killing cows!' But the reality is, I like to think I am trying to do my little bit. I will turn off a light when I leave a room; I will turn off a socket if I don't want to be using the socket. And those are tiny little things."
Paul: "Even President Obama tells you to do that."
On average we are eating twice the amount of meat we ate in 1961, the year the Beatles first performed at the Cavern club in Liverpool.
"The idea of having one type of meat for your breakfast and another type of meat for your lunch, and then another type for your dinner, and in between having your sandwiches with another kind of meat, we really do eat too much of it," says Paul.
To produce a single kilogram of beef, farmers have to feed a cow 15kg of grain and 30kg of forage. It is a highly intensive business that is ultimately not sustainable. Livestock production is responsible for 70 per cent of the deforestation of the Amazon jungle and, by 2050, the world's livestock population is expected to rise from 60 billion farm animals to 120 billion. It is a scary fact when you consider that a single cow can produce 500 litres of methane per day, which has around 25 times the global warming impact of CO2.
"I think we forget more and more that we are animals," says Stella, "and we are part of a planetary system where all of the animals are on this planet together and you are made to feel like a hippy-dippy jerk that should go and live in a tipi for even making a point of remembering."
Stella is the most vocal of the three, passionately backing up her father, shaking her head, saying "it's all money, money, money!" about the projected growth of the meat industry (world demand for meat is estimated to double by 2050) and butting in with the odd comment like: "Greed is not a good look. I was brought up to think this was not a good look. Everything in moderation." And she knows her stuff. She urges me (and you) to watch a film called Home that was made by the aerial photographer, Yann Arthus-Bertrand, and launched recently on World Environment Day. You can link to it from her website steelamcartney.com.
As she says, she tries to do her bit. Although she already incorporates sustainable and organic fabrics in her mainline collection, she also designs a capsule Green Collection which is as purely ethical and sustainable as she can make it and is sold at Barneys in New York and Harvey Nichols in London. On her website, in between pictures of models looking supremely cool and confident in her clothes, if you click on the "Green me" button, you can read Stella's eco tips -- small things we can all do to help slow down global warming. Her London shop is powered by Ecotricity. Her skincare range, Care, is made using 100 per cent organic active ingredients and is Ecocert--certified. And of course, she tells her celebrity friends off for wearing fur and she doesn't use leather.
"In my industry, there is no alternative in people's minds to leather shoes. Now I'm not making a leather shoe. I'm doing all right. We can get by. Things change. Humans are the best animals -- the best adapters on the the planet. We adapt quicker than a tree does in the rainforest."
In March, she was given an award by the Natural Resources Defence Council (which works to protect wildlife and wild places) in New York. "I was lucky enough to present that to her," says Paul. "I said that when she joined the fashion world, she first of all was employed by Gucci and my first thought, and Linda's, was 'Uh-oh, Gucci is leather city.' When you think of Gucci, you think of leather. We thought how long is it going to be before she caves in on her principles? And we waited, and we waited, and we waited, and she never did. That is a fantastic achievement... and that's what's great about new ideas, different ideas, people catch the fire, they get excited."
While Stella feels she has been pilloried for her principles, her determination seems to have paid off. Just as the fashion world has finally come round to her big idea of wearing jumpsuits and your boyfriend's jacket, we seem to have arrived at a moment when having principles is not such a bad thing.
It is perhaps no coincidence that she is the only fashion person to be included in Time magazine's annual 100 most influential people this year. Just as any father would, Sir Paul admits to having the magazine on his kitchen table, open at the relevant page -- a tribute written by Stella's friend, Gwyneth Paltrow: "Even if you are not vegetarian, somehow Stella gets you to believe. She manages to convince you (never sanctimoniously from a soapbox) that killing animals is needless and cruel and bad for the environment."
Sir Paul: "She could have caved in and we almost would have forgiven her. The pressures were so huge, but the fact is that she did not..."
Stella cuts in: "I just think I've been very lucky. I think I've been brought up in a certain way. Mary's like that, my brother [James] and sisters [Heather from Linda's first marriage, and Beatrice from her father's second] are like that. My husband's like that. It was very hard in my industry especially to have those kind of principles and I did have the mickey taken out of me until about a year ago. And people will probably read this and chuck it on their barbie and cook beef on it, but the reality is I'm more impressed by people who take a risk, and I think in this day and age..."
Sir Paul: "It's how the world changes."
Stella: "I try to keep my head down and get on with it and design pretty frocks. That's my job. And Dad makes pretty good records when he's given half an hour in between his potato mashing, and Mary's a fantastic photographer. We don't want to come across as forcing people to think a certain way, I think it's just a very valid issue and life's too short to not do something you believe in. You've only got a short little period on the planet to make something of your life."
With all of this passion and desire for change, I wonder if Sir Paul will be writing a Dylan-style protest song to promote the cause. "I do have a few sort of animal awareness songs, but they are very difficult to write. I wrote one called Looking for Changes that was applauded by Peta [People for the Ethical Treatment of Animals], which started off with 'I saw a cat with a machine in its brain', you know that picture? A hardcore picture. That made me write that,butit'svery, very hard to do and it's not my forte. Iwishit was, that would be kind of nice to be driven in that direction.
"We're going to get a bit of flak for this campaign," he adds. He can't resist singing into my Dictaphone before turning it off. "Why do we feel we need to do it? Because Meat Free Monday is a damn good idea. I mean, what are you going to tell your kids? That we can do something about it. This is one of those things that you can do."
For more details on Meat Free Monday visit www.supportmfm.org