The documentary series exploring the work of detectives from the City of London Police unit concludes with an insight into an operation to shut down a large-scale bank-cheque fraud empire. Run by a Zimbabwean gang, the scheme involved counterfeiting cheques from thousands of people, government institutions, small businesses, and even a hospice in Scotland. The criminals used an army of `mules' to cash their fake cheques for a small commission. Funds were then being transferred to Zimbabwe in the form of luxury cars, by a ringleader who viewed his crimes as payback for his native country's colonial grievances against the UK.