This is a Penny Red postage stamp from Great Britain, issued during the reign of Queen Victoria. The Penny Red replaced the famous Penny Black in 1841 and remained in circulation until 1879. Your example shows the profile of Queen Victoria in a line-engraved design, with corner check letters K – L identifying the position on the printed sheet.

The cancellation is a barred obliterator with the letters “S.W.”, indicating use in the South Western District of London. Such cancellations are prized by collectors, as they provide postal history context. The stamp appears to have been perforated (introduced in 1854), placing it among the later Penny Red issues rather than the earlier imperforate type.

This issue is significant to collectors as it represents one of the longest-running definitive stamps in British history, with numerous plate varieties. Condition, cancellation type, and plate number (sometimes faintly visible under the design) greatly affect value.