The lot, contained in a set of ten frames, took eight years to compile and will be auctioned off by Cirencester-based Dominic Winter Auctioneers on Thursday December 16 with an estimate of £10,000 to £15,000.
The signatures, spanning more than 300 years of political history from Sir Robert Walpole through to Boris Johnson featured in rare manuscripts, letters, and deeds, and were brought together by collector and dealer Hamilton Bland.
The collection, with each signature positioned next to a portrait of the corresponding Prime Minister, will be made available for public viewing three days before it goes under the hammer.
Mr Bland said: “I really enjoyed building the collection over the years – although some signatures were harder to acquire than others.
“The signatures of the more recent Prime Ministers were pretty easy to get hold of as there are quite a few on the market.
“But some of the earlier Prime Ministers, especially those that did not serve for long, were very difficult to find. For example, it took me five years to get an original signature of William Cavendish, the fourth Duke of Devonshire.
“Authenticity is everything. All of the signatures in the collection have been independently verified and authenticated, so it’s a real piece of history.
“None of them are prints – they were all signed properly by hand.”
Describing the collection as the only one like it in the world, Mr Bland added: “Boris Johnson himself described it as ‘remarkable’ in a letter to me. I’m really excited to see how it does when it goes under the hammer.”
The collection starts with Sir Robert Walpole and is rounded off by Mr Johnson, who is featured in his own frame.
Chris Albury, auctioneer and autographs specialists at Dominic Winter Auctioneers, said: “This is such a comprehensive collection of British political history, which is beautifully displayed in these 10 frames.
“It perfectly distils the political journey our country has been on since 1721, with political parties coming and going over the years, and through major events such as the American Declaration of Independence, the French Revolution, and two World Wars.
“We are expecting plenty of interest in this collection from private collectors from across the globe and we are very much looking forward to the auction in December.”