The EU limits the import of certain textiles and clothing goods manufactured in Belarus and North Korea. These quotas are administered by an import licensing system where you need an import licence in order to be able to import into the UK or EU.
The Import Case Management System (ICMS) system allows importers of goods, to make completely electronic applications for import licences, subject to Department for Business, Innovation & Skills (BIS) Import Licensing Branch import controls. This should reduce the administrative burdens on business, making it easier for them to apply. It should also speed up the time it takes to receive an import licence.
You can apply for a new import licence at www.ilb.bis.gov.uk. You need to register on the system before you can use it, see How Do I Register for Import Licences?.