Royal Doulton tobacco jar

I found this royal doulton jar last week . When I first saw it it was black with dirt, and I thought it was made of metal. It has a royal doulton stamp on it but no model number or makers signature. Just a black stamp that I can't make out. The silver rim is dated 1920 and was retailed by George Betjaminn & sons. Any help on the designer would be much appreciated, thanks for looking.