CRB (DBS) check is necessary for the process of PCO licence application. Transport for London demands all the PCO licence applicants to run an Enhanced Criminal Records Check from the Disclosing Barring Service that was known as CRB earlier, by the service provider TMG CRB.
The TfL has termed TMG CRB to give CRB application services to all the private hire drivers. One can apply the form by post or online. You are required to have the full UK or EEA driving licence, your passport or National ID, your N.I number, your recent bank statement or utility bill, your current and valid email address and home address, information regarding your change of name if any and certificate of good conduct and cases of conviction if any.
The CRB (DBS) goes through your records from the sources including the police department and search for any cautions, criminal cases, convictions, warnings, etc. If you have any criminal history filed, there is a chance of you becoming ineligible for PCO licence or becoming acceptable.
PCO Licence London will assist your queries for the online CRB checking process.