Foreign Office Minister Alistair Burt said he was "deeply dismayed" at the appeal verdicts and called on the regime to respect "fundamental liberties".
"At the time these individuals were sentenced, reports which were acknowledged by the Bahrain Independent Commission of Inquiry suggested that some had been abused in detention, denied access to legal counsel and were coerced into confessing," he said in a statement.
"I call on the government of Bahrain to meet all its human rights obligations and guarantee its citizens the fundamental liberties to which they are entitled.
"I am deeply dismayed at the decision."
Eight of the opposition figures are serving life sentences for alleged plots to "overthrow" the regime of the strategically important Gulf state.
An uprising against the Sunni Muslim ruling family began nearly two years ago with demands for improved rights for the Shia majority.
Troops were brought in from neighbouring states to quash the Arab Spring-inspired movement and there have been at least 55 deaths and thousands jailed.
The authorities claim Iran is behind the protests and have offered some reforms, but the proposals fall well short of opposition demands.
MPs on the Commons foreign affairs committee criticised the UK Government in October for not including Bahrain on the Foreign Office list of "countries of concern".