The new bank note was unveiled in Inverness Enlarge Image

The new note features a picture of the castle in recognition of the "growing significance" of the Highland capital.

It shares the honour with castles at Edinburgh, Culzean, Balmoral, Brodick and Glamis which appear on other notes.

The bank decided to introduce the note after a suggestion by staff. The last time a �50 note was issued by the bank was in 1727.

The idea for the note came about when RBS Group Chief Executive Sir Fred Goodwin visited the Harbour Road branch in Inverness.

Central banks

Managing director Ewen Munro said: "As he talked to staff they commented on the fact that we didn't have our own �50 note and the idea of launching it was born.

"It is entirely fitting that Inverness Castle should therefore be picked to illustrate this note."

Inverness was awarded city status in 2000, making it the country's fifth city.

In most countries it is only the government, through its central bank, which is permitted to issue currency.

But in Scotland three banks are still allowed to issue banknotes.

Commerce and culture

All Royal Bank of Scotland notes bear a portrait of Lord Ilay, first governor of the bank, on the front.

On the back are illustrations of some of Scotland's famous castles.

The �100 features Balmoral in Aberdeenshire, the �20 Brodick on Arran, �10 shows Glamis in Angus, the �5 Culzean in Ayrshire and Edinburgh Castle is displayed on �1 notes.

The Bank of Scotland and the Clydesdale Bank also issue their own notes.

Sir Walter Scott features on the front of Bank of Scotland notes.

On the back, are illustrations of various aspects of Scottish industry, commerce and culture.