By Ollie Stone-Lee BBC News Online political staff

David Low is acclaimed as the 20th Century's greatest cartoonist, the man who scarred the appeasers with his pen, but the public is only now getting to see the originals of his work.

Low's most famous creation, that reactionary caricature Colonel Blimp, entered the dictionary as another lasting legacy of a master satirist.

He was exposing the evils of fascism and Nazism when many politicians were ignorant of their menace

Tony Banks Labour MP

Now Parliament's Westminster Hall - at the heart of what was once the office of many of Low's victims - is the stage for a major exhibition of his work and the history it depicts.

The exhibition, sponsored by the Political Cartoon Society and BBC History Magazine, opens on Thursday and runs until the end of October. Entry is free.

Appeasement warnings

Tony Banks, chairman of the House of Commons Committee on Works of Art, said Low was a prime example of how cartoonists could be both true artists and significant political commentators.

"He was exposing the evils of fascism and Nazism when people around this place - and in the newspapers - were ignorant of their menace," Mr Banks told BBC News Online.

Colonel Blimp entered the dictionary - copyright Atlantic Syndication

The Labour MP is himself an avid collector of political cartoons and is bequeathing his collection to Parliament when he dies.

"It is right we recognise the pivotal position of the cartoonist in politics," said Mr Banks.

Wonderful portraits of politicians often did not tell as much as cartoons about the personalities and the political history involved, he argued.

Parliament has contributed some of the cartoons for the exhibition but has hundreds more by other artists, such as James Gillray and John Doyle.

Mr Banks hopes Parliament in future can house that collection in a new museum of political cartoons inside the Palace of Westminster.

Whatever politicans said about being lampooned, they hated it much more when they were not drawn, he added.

Racism warnings

Many of Low's most famous works are featured in the exhibition, which aims to portray 40 years of British history through his cartoons.

Among them All Behind You, Winston depicts Churchill's new wartime coalition government in 1940.

And there is the equally famous Very Well Alone - showing Britain fighting on against Germany after France's surrender.

David Low drew more than 14,000 cartoons

That cartoon is also signed by Churchill, who sent it to the air chief marshal in charge of coastal defence during the Battle of Britain.

There is cutting commentary too of Neville Chamberlain's appeasement stance.

Greg Neale, editor of BBC History Magazine, stressed Low had also brought lesser known issues such as racial prejudice and calls for African independence to public attention.

Outsider

He argued Low, and other cartoonists, had not only been able to encapsulate the mood of the nation at key periods, but also shape public opinion too.

Born in New Zealand and working in Australia before arriving in Britain in 1919, Low had an outsider's perspective on the UK.

Curator Tim Benson says cartoons tell much about history

Colonel Blimp was intended to portray all he disliked in British politics - extreme isolationism, impatience with common people and their concerns, and little enthusiasm of democracy.

The character emerged after Low overheard two military men sweating in a Turkish bath talking about how cavalry officers should be able to wear their spurs inside tanks.

Tim Benson, the exhibition's curator, said most of the original cartoons belonged to private collectors and were going on public show for the first time.

The history teacher added: "Cartoons are a wonderful way of learning about the past."

Exhibition opening times:

9 May-2 August - 0900-1300 BST Monday to Thursday, 0900-1700 Friday

3 August-28 September - 0900-1800 Monday to Saturday, 0900-1800 Sunday

1 October-31 October - 0900-1300 Monday to Thursday, 0900-1700 Friday.

"The Morning After" about the Wall Street Crash - copyright Atlantic Syndication