To like the "Thatcher" exhibition you have to like contemporary art. I do not. When confronted with a multiplicity of squares bearing such inscriptions as "Welcome to earth, population five billion", or a smiley face, and told that it has something to do with Margaret Thatcher I am profoundly unimpressed. I am not to be moved even when informed the work is by Keith Tyson, who won last year's Turner Prize. If my novels were just jumbles of unintelligible text, conveying nothing to the reader, they would not be published, but there seems a ready market for meaningless paintings.
I next turn to a large sculpted dog standing on a map of the Falkland Islands. (I am glad someone told me it was the Falkland Islands because until then I thought it was a giant jigsaw divided in two.) It is not a British bulldog, but it is a pretty fierce-looking animal, painted the colour of a Sea Harrier and bearing a target over one eye. Humph. Well at least it has shape, is recognisable and conveys some sort of message.
The same artist, Kenny Hunter, is also exhibiting a sculpture of the former prime minister, entitled Three Foot Thatcher. It depicts a diminutive Margaret, complete with handbag, standing on an oil drum, her arm flung out in a rhetorical gesture. The size is supposed to be significant: apparently it is seeking to diminish her stature.
Don't even try, Kenny. This lady was the first woman to become prime minister. She stayed prime minister for 11 years, won three elections, cut the trade unions which were then too powerful down to size, rid us of so many state monopolies, and stood up to communism so successfully that it fell. Thanks to her, thousands of people who thought property ownership was a privilege reserved for others now have their own homes. Hunter's statue is a bit like Oxford University's refusal to award its former undergraduate an honorary degree - a petty wilfulnessnot to recognise greatness. It would, however, be ungenerous not to pay tribute to Hunter's technical skill, which is outstanding.
It was a relief to turn to Paul Graham's portrait of Thatcher at the 2002 Politico's dinner. I was there saying the grace on that occasion:
Lord, we thank you for our loaves and fishes,
Please bless those who serve and wash the dishes,
And because there's none to match her,
We thank you, Lord, for Lady Thatcher.
Despite the levity of that grace it was a sombre occasion. The Queen Mother had just died but there was also the moment of truth for Thatcher herself. Her doctors had just told her to make no more speeches and, on an occasion celebrating her greatness, she was confronted with the reality of age and illness. Graham's picture captures well her mood that evening: determined still but vulnerable.
On the same wall is a very different portrait, by Sean Landers, showing Lady Thatcher with the nose and lips of a clown. One's first instinct might be to think he is mocking, but closer inspection reveals an endearing old lady behind the clown's nose. It is probably the only truly affectionate portrait in the room.
A large painting of two butterflies by John Newsom attempts to capture the world as seen through the eyes of the young Margaret Roberts, while an impressive impasto by Keith Coventry shows the bombing of the Grand Hotel. A vase by Grayson Perry gives us Thatcher suckling a child. A pretentious piece of nonsense (with a slogan proclaiming "left is the new right") by a guy calling himself Bob and Roberta Smith contributes as little as is possible; but a largely blank piece of paper with the words "something on the left, just as you come in, not too high or low" and billed as Perfect Opposition Conceived During Thatcher's Reign, by Martin Creed, raises a smile.
As for Erwin Wurm's contributions, I advise you to give them a miss unless you can tell me what a man with his head in a lady's jersey has to do with Margaret Thatcher.
The finale entails going into a room, bare but for a television screen on which plays Mark Wallinger's version of Thatcher's 1982 conference speech. The words are as she delivered them but the only images on the screen are of the former prime minister with her eyes shut. Every time there is applause the screen goes blank. This chap is also a Turner nominee, and the title of this piece of interpretation is The Sleep of Reason. Presumably Wallinger is referring to his own brain.
So it is all there: the child, the mother, the warlord, the victim of terrorism, the triumphant politician, the vulnerable woman, but somehow it lacks cohesion. You feel there is something missing, something that might bind it all together, might cause you to depart in a thoughtful mood, make you feel you had learnt something or confronted a new dimension. There is indeed something missing - reality.
"Thatcher" is at the Blue Gallery, London EC1 (020 7490 3833) until 17 May
Ann Widdecombe is MP for Maidstone and The Weald