Since 1862 the Worcester factory produced porcelain under the name Worcester Royal Porcelain, which is now commonly known as Royal Worcester. Before 1862 the porcelain factory had several owners and different names; we have compiled a very brief history of the porcelain factory dating back to the first period 1751 when the secrets to soft paste porcelain were first discovered by Dr. Wall. This is the reason you still the number 51 in the centre of the back stamp.
The Royal Worcester section relates to all bone china marked Royal Worcester, hence dated from 1862 up until the end of the 20th century. We only stock antique, collectable and vintage items made in Worcester UK, before any porcelain was made under contract and manufactured outside the UK (this happened as the factory approached it's final years).