Huddled round a table among the 14km of roller racking, almost hidden among the shelves containing in excess of 200,000 boxes, sit five thoroughly absorbed volunteers, patiently labelling and packaging little plastic bags containing small, metal objects.

Cherstin, Vanessa, Melvyn, Tim and Lisa are volunteers at the Museum of London’s archaeological archive, in Hackney, and are helping the museum with its Unearthing Barnet project.

If you’ve ever wondered what lies beneath your feet as you walk around the borough of Barnet, now is your chance to find out, as the volunteers, along with the museum’s archaeological collections manager, Adam Corsini, will be at Brent Cross shopping centre next week showing you just what’s there – the remnants of a 12th Century earth-and-timber motte and bailey castle belonging to Geoffrey II de Mandeveille, the first Earl of Essex, situated in South Mimms, just outside Potters Bar.

“Unearthing Barnet is part of the larger Unearthing London scheme,“ explains Adam, who has been training the volunteers one day a week for six weeks.

“And we’ll be taking what we do with the volunteers here at the archive to Brent Cross, so the public can have a go at archiving and packaging and documenting the artefacts themselves.“

The volunteers have been busy repackaging, labelling and documenting boxes of artefacts that have been excavated from the site since the 1960s, often by local amateur archaeological societies, whose standards of recording and storing were, shall we say, different from today’s.

“There was a lot of effort that went into the excavation side back then,“ says Adam, who lives in Barnet, “but that sort of dropped off when it came to the archiving side. So what the volunteers are doing is getting the boxes of artefacts up to today’s standards.“

The volunteers show me what they’ve been working on this morning.

“It’s very exciting today,“ says Cherstin, a former teacher from Finchley, “we’ve been dealing with a lot of pottery and ceramics so far, this is the first time we’ve really handled any metals.“

She and the others are sorting through brooches, buckles, knife studs, pins, nails and decorative motifs from wooden chests, among other things.

“It’s been really interesting,“ Cherstin continues, “I didn’t think we’d get as much in-depth information as we’ve been getting and what I really like is the diversity of what we’ve been doing. It really deepens your understanding and gives you a real respect for the objects.

“At the start, we thought ‘Oh, this is just pottery’, but they’ve shown us how we can tell, from a tiny little fragment, that it was part of a type of pot, for a type of person. It’s sort of like detective work, it’s really exciting.

“And relating it to your local area is phenomenally important – it makes much more sense if you imagine what people were doing in that space that you walk through every day.“

Vanessa, a tour guide in London, agrees. “I really wanted to get involved in something like this that was local. I’ve learnt so much! It’s interesting seeing all the little buckles and bits of jewellery, they make the history quite personal. You can relate to that – somebody was wearing that, somebody was using that. It’s been very exciting.“

The South Mimms castle is a very important site for Middlesex archaeology.

Geoffrey II de Mandeville was custodian of the Tower of London in the 1140s, when King Stephen inherited the throne from his uncle King Henry I, whose daughter Matilda’s claims to the throne led to a civil war, and Stephen was captured by Matilda’s army for about seven months.

“De Mandeville appears to have been sitting on the fence, playing Stephen and Matilda off each other,“ says Adam, “and he managed to get away with supporting them both. They both issued him charters to build a castle anywhere on his land, which went from Berkshire right over to Essex.“

Artefacts recovered from the site suggest that, far from simply being a defence, the castle was also used for leisure and recreation, and to demonstrate de Mandeville’s status – with expensive rings and earthenware having been uncovered alongside everyday pots and pans, and hunting implements such as arrow heads.

Melvyn, who works for Transport for London by day, is studying archaeology in evening classes, so the Unearthing Barnet project has been a joy for him.

“I wanted to gain experience working with artefacts,“ he says, “the whole process of dealing with them and learning the story they tell you about the past, and the long history of Barnet, where I live.“ Tim is a member of Hendon and District Archaeological Society, a number of whose finds are stored here in the archives.

“I was mad on archaeology when I was a kid,“ says the retired town planner and computer programmer from Finchley, “but then I went to university and got married, but I retained a background interest. Now, having the opportunity to handle all this stuff that’s hundreds of years old, you think ‘Wow’. I’m looking forward to perhaps volunteering here again.“

Lisa, who lives in Muswell Hill, teaches printmaking in East Finchley, sums up the general feeling of the group. “It’s amazing how into everything we’ve all got,“ she laughs. “Today, with the metal objects, was very different and exciting, but before, when we were going through the pottery, we all got excited to find a piece with a bit of glaze on! I’d definitely like to do something like this again.“

  • The volunteers will be at Brent Cross, Prince Charles Drive, Brent Cross on Thursday, March 13 and Friday, March 14