A construction technique that links Stonehenge with one of the modern world’s most beloved children’s toys has been displayed in an image of the ancient temple taken from an unusual angle.

The rare photograph, which is believed to have been snapped from a hot air balloon, shows the prehistoric builders of Stonehenge used a method of locking together the giant stones familiar to every fan of Lego.

On the top of the towering upright stones, Stonehenge’s clever and determined craftspeople fashioned smooth knobs that fitted snugly into corresponding holes carved into the weighty lintels that were placed on top of them: just like huge pieces of Lego.

A view of the top of one of the stones taken in 1994. Photograph: www.nickwhite.uk/English Heritage

Susan Greaney, a senior historian at English Heritage, which looks after the site in Wiltshire, said the photograph illustrated the skill of the builders more than 4,000 years ago – and their determination that it should stand for millennia.

“One of the big questions is why Stonehenge was constructed with such precision engineering,” she said. “It may well be simply that they wanted to make sure it lasted a very long time.”

The stone pictured is part of the outer circle. It was one of 30 upright sarsen stones capped by horizontal lintels.

Most stone circles built at the time were constructed out of blocks of stone left pretty much in their natural, rough state and simply raised upright. But as the photograph shows, Stonehenge was more sophisticated.

The uprights and the lintels, both made of local sarsen stone, were locked together by means of a joint more commonly used in woodwork – the mortise and tenon. The tenon, in this case the rounded protruding peg, on the top of each upright fitted into a hole, the mortise, hollowed out in the underside of the lintel. The end of the lintels were tied together using another woodworking technique – tongue and groove joints.

It was certainly effective. Of the 30 upright stones, 17 still stand and five of the lintels remain in place. The lintels that would have rested on the stone in the picture, however, have fallen, exposing the tenons.

Greaney said the Stonehenge builders’ Lego-like method had stood the test of time. “Putting unworked sarsens as lintels on top of the uprights would have been pretty unstable,” she said. “Our presumption is that there were similar timber monuments at the time of Stonehenge in which mortise and tenon joints were probably being used.

“They don’t survive because they have rotted away. Stonehenge is the only one we have with this sort of working and shaping. It’s exactly like Lego. We sometimes say to our schoolchildren who visit that Stonehenge is just like Lego.”

English Heritage dug the striking image out of its archive and posted it on its Twitter feed, pointing out the Lego link.

“This is a rarely seen view of the top of one of the giant sarsen stones. The protruding tenons are clearing visible and the corresponding horizontal lintel stone would have had mortise holes for them to slot into. A bit like early Lego!”

The Danish company spotted the message and tweeted back:

ah, where it all began❤️ — LEGO (@LEGO_Group) April 14, 2020

Lego’s origins lie more directly in the workshop of Ole Kirk Kristiansen, a carpenter who more than a century ago began making doors, windows, kitchen cabinets, cupboards and coffins before developing children’s toys.

Clearly, like the builders of Stonehenge, he was familiar with woodworking joints such as tenons and mortises.

A Lego spokesperson said: “As a company that aims to inspire and develop the builders of tomorrow, it was something of a surprise to see us linked to prehistoric builders; but we were humbled to be mentioned by English Heritage in their tweet comparing the monuments’s stones with Lego bricks.”

Another builder impressed by the photograph was Tim Daw, who in 2014 constructed a long barrow – a chambered tomb – for cremated remains in the Wiltshire village of All Cannings.

“I think it’s an amazing picture,” he said. “When we built the long barrow it became clear how impossibly difficult sarsen stone is to work. It’s as hard as granite. We didn’t actually try to shape any of our sarsens because they are so hard. The fact that the makers of Stonehenge banged away at them to create those intricate joints is mind-boggling.”