PCN code 21: parked wholly
What this contravention code means, and how to appeal it · On-Street
Code 21 means the council or TfL recorded your vehicle as parked wholly or partly in a suspended bay or space. A valid permit or payment that simply didn't show, or signage that wasn't clear at the time, is a real basis to challenge this rather than pay it.
Full description on the ticket: “Parked wholly or partly in a suspended bay or space.”
Letter after the code, like 21a?
A letter after the number narrows down the exact circumstances: a means permit holder only electric vehicle charging bay, b means business bay, c means buses only, d means doctor's bay, e means car club bay, f means free parking bay, g means motorcycle bay, h means hospital bay, l means loading place, m means parking meter, n means red route, p means pay & display, q means market traders' bay, r means residents' bay, s means shared use bay, u means electronic payment, v means voucher, x means disabled bay, y means electric solo motorcycle bay, 1 means electric vehicles bay, 2 means goods vehicle loading bay, 5 means dedicated disabled bay, 6 means hotel bay, 7 means taxis only, 8 means zero emission capable taxis only, 9 means electric vehicle car club bay. We factor the exact suffix into your letter automatically.
Can I appeal this?
Yes. This is a statutory Penalty Charge Notice from a council or TfL, not a private charge, so you have a formal right to challenge it before it escalates into a Charge Certificate.