In what year was the fifty pence coin introduced into general circulation in the UK ?

The British decimal fifty pence (50p) coin is a unit of currency equalling one half of a pound sterling. It is a seven-sided coin formed as an equilateral-curve heptagon. Its obverse has featured the profile of Queen Elizabeth II since the coin’s introduction in 1969.

In 1967 the Deputy Master of the Royal Mint approached the Decimal Currency Board to ask for their advice on the introduction of a new coin. The 10 shilling note then in use was lasting only five months and it had been suggested that a coin, which could last fifty years, would be more economical. So, although decimalisation wasn't introduced into the UK until February 15th 1971, the 50p coin was introduced in 1969 when it was still known as 10 shillings.