Elizabeth II, £5 Queen Mother 90th Birthday, 1990
In 1990 the late Queen Mother celebrated her 90th birthday and the Royal Mint issued a special commemorative £5 piece to honour that event. They also issued a specimen example in an early type of bubble pack, not as fancy as the modern packaging, not as expensive as the modern ones either.
You have a crowned cipher on the reverse with the dates 1900-1990 and H. M. the Queen on the obverse. These are still mint sealed, in a smaller package which is easier to store. We found 25 of them in one of the vault rooms and while they last, you can have one for a great price!