3ft x 5ft United Kingdom Flag - UK Polyester British - Union Jack Online Stores - 3 x 5 - Poly Britain Flag This 3ft x 5ft United Kingdom Flag is a printed flag that is made of a good quality polyester. It has been finished with a strong header with brass grommets. The UK flag's design is so because it combines the crosses of the 3 countries united under one Sovereign - the kingdoms of England and Wales, of Scotland and of Ireland