Berlin police say that Luka Rocco Magnotta is being questioned and will be brought behind closed doors before a judge, who will read out the international arrest warrant later.
Officers arrested him on the site, he did not put up any resistance. He says he is the wanted person.
Interpol has placed Magnotta, who was last believed to be in Paris, on the equivalent of its most-wanted list.
More top news
The Prime Minister and the Leader of the Opposition praised the courage of Britain's armed forces in a Christmas message to troops.
Nick Clegg has vowed to avoid appearances on reality shows like I'm a Celebrity Get Me Out of Here! when he stands down as an MP.
Immortalised in the film Zulu, the Battle of Rorke's Drift is an iconic episode of British military history.