It's slightly before Victoria's reign, but does show how black people were an integral part of major British events as far back as 1805.
I was listening to a piece on Radio 4, where a historian was saying that 20% of the sailors in the British fleet at the Battle of Trafalgar may have been black. He also pointed out that there is a figure of a black sailor on the plinth of Nelson's Column in Trafalgar Square, and another black sailor in the painting of the Death of Nelson now held at the Walker Art Gallery, Liverpool. As he said, the painter and sculptor weren't putting those figures in to be politically correct - they were putting them in because the sailors had been there.
After doing a little research myself, I see that it's not actually that easy to determine how many black sailors there were - the muster rolls didn't indicate race, but they did usually say where the sailor came from. Here's the list from the Victory, taken from an article in the Independent:
"Nelson's Navy may now be seen as being as English as boiled beef, but the Victory muster book listed only 441 English on board on the morning of the battle. The remainder were a seafaring United Nations: 64 Scots, 63 Irish, 18 Welsh, 3 Shetlanders, 2 Channel Islanders, one Manxman, 21 Americans, 7 Dutch, 6 Swedes, 4 Italians, 4 Maltese, 3 Norwegians, 3 Germans, 2 Swiss, 2 Portuguese, 2 Danes, 2 Indians, 1 Russian, 1 Brazilian, 1 African, 9 West Indians, and three French volunteers."
Also on the Victory was "William Brown", who was dismissed from the British Navy in 1815 after serving eleven years and becoming captain of the foretop on the Charlotte - because she was female. Two women are also in the painting of the Death of Nelson, on board the ship as wives of members of the crew.
57 of the crew of the Victory died during the battle or of their wounds in the next few days, with 102 being wounded.