Walk the length of Market Street, Harbourton's main shopping street, and you will pass 23 empty shops. Some have been vacant for a few months. Others have been empty for more than five years, their windows covered in faded posters, their doorways collecting leaves.

Many residents assume these shops are empty because no one wants them. A six-month investigation by The Wire suggests the picture is more complicated.

Using land registry records, company filings, planning documents and interviews with landlords, would-be tenants, agents and council officers, we identified the owners of every vacant ground-floor retail unit in the city centre — 61 in total.

We found that 22 of them, more than a third, are owned by just three companies.