Looking for something to do in the Easter holidays? Prof Ged Martin suggests a trip to see a historic painting depicting a borough story

If you’ve ever strolled across Trafalgar Square, you’ll have seen the National Gallery.

Architect William Wilkins wanted to build “a Temple of the Arts”. Unluckily, he was palmed off with stubby second-hand columns. His building resembles an ancient Greek bungalow.

If you don’t feel you’re into art, the National Gallery can seem off-putting.

With 2,300 pictures, where would you start? How could you make sense of them?

Allegories of nymphs, portraits of queens and kings – what do they mean to us?

Well, here’s a start.

Trot up those stone steps, and head for Room 63 in the Sainsbury Wing. Look for the Wilton Diptych – and its Havering story.

A diptych was a portable altar piece, two wooden boards hinged together, which opened like a book.

This one was painted about 1395, by an unknown artist, for King Richard II.

It’s small and portable. The king took it on his travels, to be set up wherever he attended Mass.

We know he visited his royal palace at Havering-atte-Bower in 1397, on his way to murder his uncle. Local people may have glimpsed the diptych then.

After 600 years, the colours are wonderful. In the right panel, angels in soft blue dresses look like a Gospel choir.

The paint medium is called tempera, based on (of all things) egg.

I’d always assumed it was an oil painting. Maybe I’d confused diptych with dipstick.

On the left panel, the young king himself kneels in prayer, wearing a golden cloak.

Behind him stand three saints.

One is the king’s special protector, John the Baptist, in a beggar’s ragged outfit.

The others are St Edmund, king of East Anglia, martyred in 870 AD, and Edward the Confessor, who ruled England from 1042 to 1066.

St Edmund was tied to a tree and shot by invading Danes. He holds the arrow that killed him (there were no guns in those days), and very nasty it looks too.

St Edward holds a ring. That’s our clue.

Legend claimed that a beggar once asked Edward the Confessor for a hand-out. The saintly king was at his rural retreat and had no cash on him. Instead, he took a valuable ring from his finger and handed it over.

It turned out that the beggar was really John the Baptist.

That’s surprising, since John the Baptist’s head had been cut off a thousand years earlier. It was presented to a lady called Salome whom he had offended by his preaching. That’s the origin of our phrase, “having his head on a plate”.

Legend also claimed that the place where the two had met became known by the words used by the king in handing over his gift: “Have ring”.

It’s a pretty weak explanation for the name “Havering”.

King Richard’s patron saints didn’t do him much good. He was deposed in 1399, and murdered soon afterwards.

But Edward the Confessor was popular locally. When the people of Romford built a new church, between 1407 and 1410, they dedicated it to him.

Romford’s first post-Reformation Catholic church, opened in 1856, also honoured St Edward the Confessor.

A local secondary school bears his name.

The shield used as the school badge is actually painted on the back of the Wilton Diptych, although it’s not on display.

If you’re not a fan of medieval art (most of us aren’t), head across to Room 34 when you’ve seen the diptych, and enjoy the portraits and landscapes by British artists like Constable. Some were painted in Essex.

It’s worth preparing for your visit by identifying the pictures you’d like to see on the National Gallery website.

Admission is free. There are gift shops and smart eating places.

Nobody can “do” the whole of the National Gallery in one visit. Start with the Havering connection – I’m sure you’ll go back!