Researchers in Britain are about to embark on a 10-year, multimillion-dollar project to build a computer — but their goal is neither dazzling analytical power nor lightning speed.

Indeed, if they succeed, their machine will have only a tiny fraction of the computing power of today’s microprocessors. It will rely not on software and silicon but on metal gears and a primitive version of the quaint old IBM punch card.

What it may do, though, is answer a question that has tantalized historians for decades: Did an eccentric mathematician named Charles Babbage conceive of the first programmable computer in the 1830s, a hundred years before the idea was put forth in its modern form by Alan Turing?

The machine on the drawing boards at the Science Museum in London is the Babbage Analytical Engine, a room-sized mechanical behemoth that its inventor envisioned but never built.

The project follows the successful effort by a group at the museum to replicate a far simpler Babbage invention: the Difference Engine No. 2, a calculating machine composed of roughly 8,000 mechanical components assembled with a watchmaker’s precision. That project was completed in 1991.

The new effort — led by John Graham-Cumming, a programmer, and Doron Swade, a former curator at the museum — has already digitized Babbage’s surviving blueprints for the Analytical Engine. But the challenges of building it are daunting.

In the case of the Difference Engine, a complete set of plans existed. The Analytical Engine, by contrast, was a work in progress, as Babbage continually refined his thinking in a series of blueprints.