Britain's biggest collection of antique loos is up for sale for £300,000 - including a potty with Hitler's face on the bottom.

The never-before-seen Thomas Crapper Collection belongs to Simon Kirby who has spent the last 40 years amassing the hoard featuring hundreds of rare toilets.  

They include ornate WC pans, polished wooden loos seats, a toilet from Harrods and thunderboxes dating back between the 1830s-1960s.

The 57-year-old is now reluctantly parting with his quirky collection of 1,200 items, which is up for sale to those feeling flush for £300,000.

Simon began collecting the pieces gradually as a personal project when he was managing director of Thomas Crapper & Co.

It formed the basis of a private museum at the Warwickshire-based company, which he left eight years ago to become a consultant to the Royal Household.

Simon Kirby has spent the last 40 years amassing the hoard (image via SWNS)

There are also hundreds of antique brass taps, basins covered in floral decorations and huge cast-iron baths, some panelled in mahogany. 

One of the baths with silver plated taps belonged to King George V from the Royal Train while there's also 200 salesman samples of miniature loos, baths and basins. 

Simon, of Shipston-on-Stour, said: "These pieces are now so rare, the collection could not be assembled today.

"I'd say it all started when I was a strange 11-year-old boy and I have my mother to thank for it really. 

"She was a book dealer and gave me a book called Temples of Convenience - which is about lavatories. Its full of pictures of decorated Victorian lavatories.

"My interest started then and I suppose my first museum was my bedroom. Some of the items in the book are now in my collection. 

"Then at 17-years-old I started a business salvaging and restoring antique sanitary ware.

"I sold to people who wanted period bathrooms and things like that and it progressed from there to running Thomas Crapper and I thought why stop now.

"As I no longer run a Victorian sanitaryware company, I cannot justify keeping the collection. It is time for it to be explored and enjoyed by the public.

"Old bathroomware of this quality and condition is seldom found these days.

"Most of this hoard was gathered in the 1980s and '90s so this is a unique chance to acquire a large number of very rare pieces." 

It is hoped a museum might buy the collection as a whole but if a buyer can't be found Simon will sell it off piece-by-piece.

Aside from Thomas Crapper, the collection features highlights from other makers, including George Jennings, Twyfords, Shanks & Co. and Royal Doulton. 

The Hitler potty was designed by Crown Devon and features "Have this on 'Old Nasty' Another violation of Poland" written around the side. 

The exhibits are described as being "mostly in extraordinarily fine condition" charting the development of bathrooms, in particular loss, from the 1830s to the 1960s. 

Sara Morel, CEO of Salvo, an architectural salvage firm, said the company had been asked to help rehome the collection to "preserve its future"

She said: "Salvo has continuously encouraged reuse to reduce the amount of architectural salvage that is downcycled or destroyed, so we were asked to help promote and rehome the Crapper Collection to preserve its future. 

"Touring the private museum was fun, insightful, and a privilege as the video shows, each piece holds stories that must be saved and shared.