Every now and then, I take stock of the agricultural state of my affairs. Something bad usually triggers this inventory. This week, it was British Sugar. The beet factory rejected 400 tons of our sugar beet damaged by the frost in December. The beet was worth £10,000, although out of that figure comes the cost of planting, growing, harvesting and carting it nine miles to the factory in Bury St Edmunds, bills that still have to be paid.

Then there’s the ignominy of a mountain of stinky sugar beet back on the farm. We tried julienning a bushel for our cows and sheep, but they’re as picky as teenagers and won’t touch beet that smells like stewed cabbage. They stick to the sweet-smelling hay that costs £6 a bale, up from £4 a bale last year.

When the agricultural accounts don’t add up, the romance of country life hits a certain lull. I find myself thinking of city life the way city folk think of cows. I dream of black taxis, Pret A Manger soups and the free London Evening Standard, and the train from Stowmarket to Liverpool Street feels like a magical escape from agriculture to culture.

Despite years of living in London, I’m embarrassed to confess that I’d never been to Dulwich Picture Gallery. With regret, I’ve missed John Piper, three generations of Wyeths and Paul Nash, all because I’ve been stumped by the geography. Dulwich seems as remote to me as East Lothian, but at last I Googled ‘How to Get There’. It told me to take the Orpington train from Victoria, which leaves every 15 minutes and gets to West Dulwich station in three stops, then it’s a 15-minute leafy walk to the gallery.

What finally spurred me on was the Norman Rockwell show. The (other) Spectator critic Andrew Lambeth described the artist and illustrator as a ‘master of the reactionary self-image, adept at creating American family life of a bygone age, mostly with a rural slant’, but I felt a nostalgic urge to revisit the images of my own bygone days. Even back then, I knew life was more precarious than it appeared on the cover of The Saturday Evening Post.

The gallery in Dulwich is pretty bygone, too: the first purpose-built art gallery in England. The permanent collection is worth a trip on its own, but I only skimmed it on my way to the Rockwells. It was like a visit to the American century, idealised at times, but even the sappy pictures have a truthful core. His fellow artists accused him of painting real life through rose-coloured spectacles, but some pictures startle in their timeliness.

Four paintings inspired by a speech by Presi-dent Roosevelt in 1941 could be posters for events happening in the world today. Called ‘The Four Freedoms’, they represent ‘Freedom of speech-everywhere in the world’, ‘Freedom of every person to worship God in his own way, everywhere in the world’, ‘Freedom from want’ and ‘Freedom from fear’.

The images may be a too soft focus for today’s freedom fighters, but Rockwell was no Hallmark sap. In the early 1960s, he left The Saturday Evening Post because his editors wanted him to paint more celebrities for its covers.

He went to Look magazine, where he created some of the most memorable paintings of that turbulent era, including the haunting picture of a small solitary black girl being led by federal marshals into a school in New Orleans. With his paintbrush, the artist showed America that segregation is a withdrawal from humanity.

Rockwell might not pass the Lambeth test, but he passes the Tolstoy test. The writer believed that ‘the purpose of art is the transmission to others of the highest and best feelings to which men have risen’. As for looking at life with a rural slant, I only wish we had a Rockwell in Suffolk to record the look on a farmer’s face when he’s told that his crop’s been rejected.

‘Norman Rockwell’s America’ runs until March 27