Earlier this week, in a vital scientific experiment, the London Evening Standard sent some of the paper’s premier he-men to see if they could watch the new Toy Story movie without bursting into tears.

The City editor has seen a few devastations of late, including the collapse of the entire human economic system, so he was able to keep it together when it came to this wonderful tale of toys being left behind. The crime correspondent, hardened from years on the frontline of heartbreaking depravity, managed to hold out before cracking in the final scene. Tim Nichols, the assistant sports editor, presumably has no tears left after England’s World Cup performance, so he remained dry-eyed throughout.

And your film critic? Well, let’s just say the trickle coming from the Gulf of Mexico’s BP oil pipeline cannot compete with this particular he-man’s blubathon. I’m talking sobs. I’m talking snot. I’m talking great, heaving gasps and tiny help-squeaks of sadness such as would make the weepiest actress in Hollywood lower her head in shame. The welling-up started in my toes — or somewhere deep in my childhood — and rumbled upwards throughout the film, until, near the end, it showed itself as a virtual tsunami that washed over my crimson, clawed cheeks. I tried stuffing paper into my nose and into my mouth and in my ears to stop the flow. It was hopeless. Toy Story 3 is not only a masterpiece but is the most heart-rending film I have ever seen.

Somewhere in the Disney offices in Hammersmith (where I watched the film with my daughter) a hundred Polish cleaners are still working round the clock to mop up the dreadful tears of your own correspondent. On the strength of all this, my six-year-old now believes her least favourite dolls, Tiny Tears and Patty Go Potty, are visions of stoicism and continence next to her dad.

The film starts with some of the usual Pixar panache. Things are about to change, big time, in Andy’s bedroom. The boy is now 17 and is going off to college. The toy soldiers, the parachute regiment, see the writing on the wall and they each jump out of the window and are carried off by the wind. But what about Buzz, Slinky, Mr and Mrs Potato-Head, and the erstwhile Jimmy Stewart of the whole franchise, Woody? Well, they’re doomed. The inevitable turn from childhood to adulthood has several casualties. Usually first to go is the parents’ will to live, but second, every time, is THE TOYS. Andy’s mother makes him choose which toys will go into the attic and it looks like Woody might be the only token toy to survive.

A mix-up with the bags, though, means that Andy’s toys, having narrowly escaped the refuse truck, end up at the Sunnyside day centre for crazy kids, ie just kids, many of whom express a — shall we say? — more robust and perhaps less sentimental attitude to old toys charitably given. It turns out that Sunnyside has a system of government, run by the toys, that slightly resembles the system currently operating in the hoods of South Central LA. The big boss is a once-loved, now sinister, teddy called Lotso (“The Lotso-Huggin Bear”) who seems to welcome our friends to the day centre, but Woody thinks they should escape and find their way back to Andy. It turns out Sunnyside is run like a prison, and Andy’s toys are trapped with children too young to love them.

I won’t spoil it, but let’s just say the toys are set on a fur-raising adventure to escape their ultimate extinction, which might even mean the local dump and the incinerator. Along the way they meet Barbie and Ken, who live the high life, and Lotso’s sinister henchman, Baby Doll, who would happily see them off. Andy’s toys must pull together to escape this. Can they survive? Will they ever see Andy again? Can they play a part in turning Sunnyside into a happy place for toys? And, most of all, will they ever know the joyous love of a child again, justifying their existence and securing their future?

As the tear-jerking cliché says, when we are no longer children we put away childish things. Toy Story 3 taps into one of the most ordinary sadnesses of the average life: we are all, in the end, exiles from our childhoods, and lost to the things that used to make us happy. This needn’t be a disaster, but it is sometimes deeply felt, and on the back of that feeling Pixar has made a masterpiece. The writing is just so precise and so clever; at every turn there is something moving and funny, something true, and though always sticky with sentiment, the film overcomes even that to become a little anthem to resumed youth.

The relationships between these animated characters never fail to be interesting and alive, each of them beautifully voiced, slinging joke after joke and wisdom after wisdom, and never letting up.

We can now say this is a golden period for kids’ movies. It is like American cinema in the early Seventies — the period of Raging Bull, The Last Picture Show and Chinatown — except we’re talking about animated features made primarily for children. They have never been so good.

Up, last year, was a miraculous offering that tapped, like the great mythic stories, into adventure and feeling in a way that made earlier Disney classics like Bambi and Dumbo seem almost shallow and manipulative. Toy Story 3 goes even further, bringing some of the best cinematic minds of our generation to bear on some of the good questions. Art and popularity have seldom seemed happier together.

And why are the men crying? Well, you know, the old things: remembrance of things past, you can’t go home again, the past is another country, all the matters named in literature that have somehow made it on to the screen in a children’s flick. At my screening, the children were hollering with laughter and jumping with joy and the adults quietly wept. It’s a phenomenon. The greatest movie of the year. And not to be missed at any price. Even if it ruins your image with your children for ever, it was going that way anyway, and you may as while have fun as the adventure blazes and the sun sets.