The concept.

Tate Britain's current show Conceptual Art in Britain 1964-1979 starts at that period, in the mid-sixties when art, or the idea of it, was being challenged. Was it a rarefied pursuit for the privileged chattering classes to ponder over cocktails or was it something for everyone? Did it have use beyond ornamentation?

Some young artists were frustrated by Clement Greenberg's strict definitions regarding the prevalent modernist art scene. They rebelled against the parameters imposed by using unstable, perishable materials. Often they used words instead of pictures. Art was to be read about, thought about, as much as looked at.

John Latham organised a party where guests chewed and spat out pages of Greenberg's books. Rip it up and start again. Other attention seekers included Barry Flanagan and his pile of sand and Roelof Louw's Soul City (Pyramid of Oranges) from 1967. The oranges displayed in the Tate are no longer in a pyramid but some Googling reveals they once were. Gallery visitors were once invited to take an orange and eat it. That, too, is not how they roll down Pimlico way. Which is a pity as that generous act makes more sense than a ring-fenced load of oranges placed in the art-historical context that once they stood against.

They do, however, still represent the impermanence this early wave of conceptualists sought. Art & Language exhibited mirrors and black squares parodying the very tropes of modernism and abstraction. To dismiss the previous generation's work is fair enough, to be expected even, but to have nothing to put in its place is disappointing at best, arrogant at worst.

These paintings weren't so much paintings as ideas about paintings (even though they were still paintings). That sentence indicates how self-referential and navel gazing a lot of this stuff is.

Richard Long is an interesting case though and I suspect he would've been at any time. In 1967 he created A Line Made By Walking. He walked back and forth across a field until a path became visible. The walk itself was the art. The photo, below, a mere memento. A memory of art.

If you think oranges and piles of sand reek of pretension just get a load of the room given over in its entirety to Art & Language and their smug, haughty critiques of everyone and everything. The blank maps are easily shrugged aside but life is way too short to waste time reading their earnestly dull tracts of verbal diarrhoea. Like said diarrhoea it's pretty much all shit.

Bruce McLean pointlessly poses as if for a Henry Moore plinth. Keith Arnatt, literally, eats his own words. Ed Herring fills a filing cabinet with postcards. John Hilliard uses a camera to take pictures of itself in a mirror. Mirrors crop up quite a lot which is hardly surprising when you consider the inherent vanity of much of this work. These were just art school posers fucking around to impress each other. At least Arnatt's 1969 Self-Burial is mildly amusing. Pity he didn't bury most of this art along with himself.

The fact the self-burial was shown on West German TV in nightly prime time installments shows us just how much of a foreign country the past is - and actual foreign countries are.

The big central room of the exhibition is full of even more colourless, humourless crap. It's all so bloody grey. Sue Arrowsmith framed a wall. David Tremlett rubbed graphite into file cards as he hitch-hiked around Australia. You'd think Gilbert & George would liven things up but the documentation relating to the Singing Sculpture (which is fun when seen on film) is the least interesting thing I've ever seen about them.

Richard Long and Hamish Fulton's walk down The Pilgrim's Way and their trek around Peru and Bolivia must've been interesting for them and I'm sure the views of Lake Titicaca were lovely but there's nothing for us here. Not even a stranger's holiday snaps.

Michael Craig-Martin's notorious glass of water/oak tree piece is a cute idea when you first see it. But it soon pales. To be honest this exhibition could consist of this one solitary artwork and you'd get the point. You'd get the point much quicker and much, er, pointier too.

There's so much reading of dry, academic tracts here that it starts to resemble an art gallery with the actual artworks removed and just the notices telling you about them left.

Mary Kelly's panels considering women's creative and procreative roles, and the tensions and dichotomies between them, at least inject some political get up and go into the aching arms of the movement. It's also a move away from what seems very much to be a boy's club. Alas, it's still ball achingly dull.

1977's Homeworkers, by Margaret Harrison, sees Kelly and rises her. It's much better. Inspired by the Equal Pay Act of 1975 and the way factories got round it (inconvenient night shifts, forced homeworking for women etc;) she advocated both discourse and action for the further advancement of women's rights.

Conrad Atkinson's Belfast postcard series offered a refreshingly non-partisan take on the city's role at the height of the Troubles. Again, it seems so much more relevant than the dick measuring of his more high-faluting contemporaries.

Susan Hillier's postcards aren't political at all but they are pretty and that's like a refreshing cold drink after the arid desert of academia I've just waded through. I'm actually not sure why they're even in the exhibition but I'm glad they are. Never have pictures of waves crashing on the shoreline in Bognor, Filey, and Clacton looked so beautiful.

Equally bracing, in this context, is the work of Stephen Willatts. In what's all too rare in the art world he engaged with people outside of it. Imagine that. He interviewed and photographed Mrs Moran, a pensioner who lived in a tower block. He didn't tell her what was good for her but wanted to know, and understand, how she lived and made sense of her life in an environment one assumes was very different to his own.

So, for me, British conceptual art came of age when it developed a social conscience and a political dimension. The supposed heyday, with Richard Long as an honourable exception, looks, in retrospect to be a collegiate exercise of little or no relevance outside its small group of practitioners. I'd rather clean up Tracey Emin's bedroom than spend another ten minutes in the cold, self-satisfied atmosphere of the Art & Language room again.

Thankfully there were people like Willatts, Hillier, Atkinson, and Harrison prepared to put the rather blunt tools they were handed down to work in a worthwhile manner. In increasingly political uncertain times maybe some of today's artists could learn something from the latter rooms of this exhibition. I fear, however, many of them wouldn't get past the mirrors at the start.