The book that got me started 46

SNIP

A company I worked for in the nid-1970s used OMR-OCR input forms and VDU input for rejected forms (non-standard marking-unreadable), in the later case one operator keyed the batch of data and it was then sent to a second operator to verify. ISTR that correctly read batches of OMR-OCR forms were also sent through the verification process before processing.

I also recall that the ICL Universal Document Reader, connected online to an ICL 1904A mainframe was a lot more successful at reading the forms, which came in from insurance agents (doorstep Debt Collection of small premiums, now a distant memory AFAIK) than some later (1980s) dedicated offline OMR readers at another company which were used for payroll input, where the forms were also computer printed, sent in special boxes to keep them flat etc. to and from the payroll offices, only used in an office environment and marked using the special (new Pentel) pens recommended by the manufacturer. On a bad night up to 30% (IIRC) of the forms had to be rewritten onto new blanks and resubmitted.

By the way the ICL UDR was also used, on the spare night shifts, to process parking tickets issued by the Met. Policce-Traffic Wardens in London - being out in all weathers (well maybe, there are a lot of cafes) you can imagine the possible state of the forms being sent for input.