Brief description: A quota is a ceiling on the level of imports allowed into the country. If the government impose these it will lead to an increase in the price of the product on UK markets.

Detailed description: In this diagram, if the government impose a quota of 4 million units the price will increase to £8. The area ABCD will now accrue as increased revenue to the foreign suppliers who manage to export their goods to the UK. UK firms will now be supplying more (4 million instead of 2 million before the quota), but the higher price may be hiding inefficiencies and may lead to a resource loss for the economy.