OPT is a European Union (EU) scheme that allows EU manufacturers to make similar clothing products in Belarus to those they make in the EU, using EU fabric. You don’t have to pay full import duty on the finished Belarus garments. This lowers overall costs and makes it more likely that you can compete against low cost imports from the Far East.
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?.