Drivers with convictions for serious offences including assault, housebreaking and drink-driving were issued Scottish taxi licences last year, according to recent Freedom of Information requests.
And it emerged that two licensed drivers in the Borders had charges dating back to the 1970s, related to unlawful carnal knowledge of girls under 17.
Across Scotland, local authorities approved 1,584 applications from people with convictions.
Data obtained by the BBC also shows that councils received more than 1,200 taxi-related complaints in 2014 - a small rise on the previous year.
The 1974 Rehabilitation of Offenders Act stipulates that applicants for taxi and private hire car licences must declare all previous convictions, both spent and unspent.
Each council’s licensing committee then consults with Police Scotland on the submitted taxi licence applications.
The committee will usually then discuss individual applications where objections have been raised, or inconsistencies have been detected, by the police.
A Scottish Borders Council spokesperson said this week: “Applicants are required to disclose previous convictions as part of the application process.
“All applications are copied to Police Scotland and any representations/objections submitted by them following their checks are referred to the Council’s Civic Government Licensing Committee for a determination on whether to grant or refuse a licence.”
Police Scotland said this week that it was now developing a new national IT system which would act as a “single point of reference for licences that had been granted or revoked by the relevant local authority”.