A small beaker bought with a job lot of pottery for under £100 has sold for a whopping £45,000 after it was found to be an incredibly rare piece of porcelain . The three-inch tall cup with a chipped rim was bought by accident by a lucky dealer who snapped up a tray-load of pieces because he liked another item on it . After retaining the item of porcelain he took the rest to an auctioneer who immediately spotted the potential of the blue and white beaker . Lucky : The job lot one buyer snapped up for £100 because he liked a different item in it contained a very rare beaker ( pictured ) that ended up selling for £45,000 . Hallmark : The crown and trident on the bottom of the valuable cup featured on only 20 pieces of Chelsea porcelain . Closer examination showed it was made by renowned Chelsea porcelain 266 years ago and was one of two pieces of its type in existence today . Despite this , the auctioneers remained cautious and gave the beaker an estimate of just £100-£200 ahead of its sale . But interest in the item took off as did the bidding and it eventually went under the hammer for £37,000 . With fees added on the British buyer paid £44,400 for it . It is believed the beaker once made up a high quality dining set for a wealthy family and would have been akin using cut glass crystal . On the bottom of the vessel is a seal mark of a crown and trident and only 20 pieces of Chelsea porcelain contained this mark . Chris Large , of auctioneers Peter Wilson of Nantwhich , Cheshire , said : 'Chelsea porcelain was at the top of the tree in terms of quality and was comparable to Meissen . Estimate : Cautious auctioneers at Peter Wilson valued the incredibly rare beaker at between £100 and £200 . 'The beaker would have been used for practical purposes back in the day . It was a status symbol , a bit like getting out your best crystal while entertaining today . ' A local dealer bought it in a tray-lot of items . He wanted something else on that tray and gave us the rest . ' I recognised as very early Chelsea porcelain but the vendor was n't convinced that it was . We remained cautious but after we advertised the sale we started getting calls from the Lonon trade reserving telephone lines for the auction . 'Needless to say the vendor is over the moon with the outcome . ' I have never handled an item that is rarer than this beaker and probably never will . '
The three-inch tall beaker turned out to be a very rare piece of porcelain . Made by famous Chelsea porcelain and is only one of two in existence . Trader decided to buy the lot because he liked another item it came with . He paid £25,000 for the whole lot, which was then sold at auction for more than double that amount.