Great Britain 1890 10s ultramarine (I.R. Official), SGO10Great Britain 1890 10s ultramarine (I. R. Official), SGO10. A very fine used example lettered 'GF', neatly cancelled by a crisp Dundee circular date stamp for 'DE. 31. 1901'. A scarce Official stamp in this quality of condition. These Inland Revenue stamps were used solely by revenue officials in the provinces. Mail to and from Head Office passed without a stamp. The London Office used these stamps only for foreign mail. Stanley Gibbons catalogue