One simply has to take one's hat off to a spectacular display that goes on show at the Bowes museum tomorrow.

The exhibition, initially intended to feature the hats of its patron the Queen Mother, now has more than 100 royal and contemporary hats after Her Majesty suggested to textiles curator Mrs Joanna Hashagen that she contact other members of the royal family.

This resulted in the Queen selecting 40 of her hats, the Princess Royal four and Princess Margaret eight, on top of the 50 or so offered by the Queen Mother.

Mrs Hashagen said the exhibition would show hats worn by the royals from the 1950s up to the present day, including the latest designs by top milliners such as John Boyd, Simone Mirman, Philip Somerville and Frederick Fox, who will open the exhibition.

"The royal dressers and milliners have also helped enormously, and we are delighted that what began as quite a small exhibition is now going to be a major exhibition for the summer," she added.

The hats will be on show until September 30.