"I expected the decision. I am very sorry for Singapore. I'm not sorry for myself," he said.
He will serve an extra two weeks in jail because he cannot afford to pay a Sg$20,000 ($16,150) fine imposed on top of the prison term.
Shadrake's jail term was the stiffest sentence ever imposed in Singapore for contempt and was denounced by international human rights groups campaigning for an end to executions and urging greater freedom of expression in the country.
There was no immediate comment from the British embassy.
COMMENT: Of course there has been no immediate comment from the British embassy. Along with the United States and other democratic nations, we conveniently turn a blind eye to the abuse of freedom that has been the embarrassing hallmark of Singapore's successive governments since it gained its independence. Only our "friendship" with the police state of Egypt outranks Singapore on the list of barbaric nations that we will let get away with anything because it suits our political, military and commercial agendas.