Late filing earns a penalty point rather than an immediate fine, with a financial penalty once you reach the threshold for your filing frequency, and points expiring after a run of on-time returns. Late payment is charged separately and escalates with time: nothing if you pay or arrange a time-to-pay within a short grace window, then a first penalty, then a further penalty that accrues daily, with interest running throughout from the due date. The design is deliberate and worth reading the right way — filing late is cheap, paying late is not. So if you cannot pay, file anyway and ring HMRC about a time-to-pay arrangement. They are markedly more accommodating to a business that has filed and cannot pay than one that has simply gone quiet.