Not only is the Union Jack flag a great symbol of the UK, the primary colours and the bold pattern make it a great feature within any design, I have also found some designs which use traditional English symbols to create a bold interior.
Having a quick look on the internet I came across a few interesting pieces you could use for your house.
I love the stamp rug! The deep plum colour would compliment a sleek modern interior as well as looking right at home with ornate traditional furniture. Sometimes the Union Jack flag pattern can be a bit overpowering so if your scared to add such a statement piece I would definitely opt for the stamp rug.
You can also brighten up your dining room with these bold chairs! I love the mismatch seating look and finding and restoring old chairs with the same pattern would unify them, the regal look is especially great for a formal dining space.