Officially adopted in 1960, the provincial flag of British Columbia reflects B.C.'s Shield of Arms, which is the central section of B.C.'s Coat of Arms.
The upper portion of the flag is the Royal Union Flag - commonly known as the Union Jack - and serves to symbolize the British past of the province. The crown in the centre of the Union Jack is King Edward's Crown and represents the Royal Family. It was King Edward who had approved the first provincial Coat of Arms on which the flag is based.
The lower section of the flag includes a series of waving blue and white lines, symbolizing B.C.'s geographic location along the Pacific Ocean. Beneath, a rising sun serves to represent B.C.'s location in Canada as the western-most province.
The provincial flag is flown everywhere throughout British Columbia, including at schools, universities, government buildings, and the Parliament Buildings.
There's a special reason why the Union Jack is placed above the waves and rising sun in B.C.'s symbols. When the B.C. Coat of Arms was first developed by Canon Arthur Beanlands of Victoria in 1895, the Shield of Arms had the waves and sun placed above the Union Jack. When B.C. attempted to register the Coat of Arms with the British College of Arms, the "inferior" position of the Union Jack as well as its usage (which only the monarch could grant) led to the denial of its formal registration.
In 1906, an agreement was reached with the College regarding only the Shield of Arms and the provincial motto. The motto remained unchanged, but the Shield now had to have the Union Jack above the waves and sun, and King Edward's Crown had to be placed in the centre of the Union Jack to reaffirm the rights of the monarch. It wasn't until 1987 that the remainder of the Coat of Arms was granted by Queen Elizabeth II. The Coat of Arms hasn't changed since.