The Collection: Art and Archaeology in Lincolnshire, Lincoln

If this were a journal about architecture rather than museums, there would be no problem giving the thumbs up to the Collection, Lincolnshire's new museum of archaeology and art. It would deserve five stars and three loud cheers for a job well done.

Built of pale stone and finely shuttered concrete, with numerous picture windows framing Lincoln and its magnificent cathedral, it could be a public building in a country that does public buildings in historic cities rather well - Denmark, Spain or Italy, rather than provincial England.

Cue Channel 4 architecture presenter Kevin McCloud, praising the building's airiness, origami-like shape and overall grand design. The way that it complements the Usher Gallery across the way is exemplary. But assessing the Collection as a museum is a bit trickier.

There is no denying the main gallery is a classy affair. The balance between money spent on the building and gallery fit-out feels appropriate: the standard of showcases, touchscreen computers, scenic settings and replica costume is top drawer.

The trouble is, there is only one main gallery. While by no means small, it seems small relative to the size of the museum as a whole.

Even if you add the temporary exhibition space - currently showing contemporary art to be followed by a show curated by the 2003 Turner prize-winner Grayson Perry - the galleries seem to constitute less than a third of the museum.

Given everything you pass on the way to them - cafe, shop, auditorium, three education rooms, all beautifully appointed, plus a supersized atrium - you expect something a bit bigger. Imagine a swimming pool that seems to be Olympic-sized but turns out to be 20 metres long and doesn't have a diving board.

I only hope the vague sense of disappointment doesn't reduce the number of repeat visitors. The atrium does boast swimming pool acoustics, however, exploited by an artist who has created a sound piece, broadcast from openings in one wall. People are saying something, but heaven knows what: the poor sound quality makes it impossible to hear.

Art isn't integrated into the archaeological displays, as in the Museum of Scotland, but the collection is better than most, ranging from the fossilised skeleton of a plesiosaur, log boats and the timbers of an Iron Age causeway over wetlands, to Roman gravestones and Saxon hanging bowls.

They are arranged in an attractive way, interspersed with settings such as a corner of an ancient round house, and a section of wetland that looks wonderful against the Lincolnshire views outside.

The museum places great store on the educational benefits of dressing up. You can try on a centurion's helmet and test the weight of his kit bag, while elsewhere there are no fewer than four costumes to put on, including a knight's shiny chain mail. Each is accompanied by a full-length mirror, which does odd things to the sightlines across what is otherwise an open-plan gallery space with an attractively symmetrical layout.

The mix of cased objects, recreated settings and hands-on activities is good. The long showcase containing 5,500 model Roman soldiers of the ninth legion marching on Lincoln will appeal to anyone with an eye for military spectacle in miniature or a Caesar complex. Beneath your feet you can see the Roman mosaic discovered on the site where the goods lift shaft now is.

Elsewhere, attempts to tell the site-specific history of the museum are less successful. Graphic panels scattered around the museum describe 'the history beneath your feet', but don't take this literally, as I did, because all you'll find is the highly polished stone floor.

There is a picture window in the corner of the gallery. A graphic panel describes how the view has changed over time - today you mostly see a car park and the back of a 1960s office block.

It's harder to understand the museum's treatment of history after 1700. The gallery really ends, object-wise, in the middle ages, against a backdrop of images from the beautifully illuminated and locally made Luttrell Psalter.

Despite the fact that there is a museum of modern Lincolnshire life in the city, a bit of overlap would help out-of-towners who will leave the Collection none the wiser about the cathedral up the hill, let alone historically significant events over the past 300 years.

If there is a link to the other museum it's inconspicuous. A few paragraphs of text and a timeline are poor substitutes, especially with banalities such as 'the 20th century was a time of enormous change'.

A timeline of high achievers, presumably from Lincolnshire although it's not exactly clear, puts Margaret Thatcher besides John George Haigh, the acid bath murderer, which seems a little harsh.

Above your head there is another timeline wrapping around the gallery. It concludes with men landing on the moon 40 years ago: Lincolnshire's part in the space race is unexplained, but you get a big image of an astronaut nevertheless.

The real heroes of the Collection aren't astronauts, they are the local archaeologists. At the heart of the gallery in a circular space is a veritable pantheon of excavators, amateur and professional: large images of a metal detectorist, a flint collector, some young diggers and the city archaeologist, holding aloft a particularly fine piece of Roman pottery.

Alas, whoever edited the gallery text has an eye for a dull quote. 'Our job is to promote and preserve the city's heritage,' says the city archaeologist. The audiovisual introduction in the auditorium is even more promotional in tone, complete with a galactic background and whizzy graphics.

Unless you become archaeological history in your own right, like Egyptologist Howard Carter, it is enough to let the ancestors and their artefacts take centre stage to convey the drama of the past.

Javier Pes is the editor of Museum Practice

Project data

Cost: £12m

Main funders: European Regional Development Fund, Heritage Lottery Fund

Architect: Panter Hudspith

Main contractor: Caddick Construction

Exhibition fit-out: Event Communications

Consultant: Lord Cultural Resources Planning and Management