The reasons for the decision were confidential, the board said. Last year, the tobacco industry was criticised by some lawyers for making submissions to the Legal Aid Board, asking it to refuse requests for help from litigants.
Most of the 300 plaintiffs are former or current smokers who claim that their health has been damaged by tobacco products. They brought the case after the US Supreme Court ruled last June that health warnings on cigarette packets did not give tobacco companies immunity from litigation.
After the American decision, two London law firms asked to hear from smokers, former smokers and passive smokers who felt their health had been harmed. The firms were keen to hear from people who took up smoking in the 1960s after studies started linking cigarettes to cancer but before health warnings appeared.
But last November, the American case was dropped. Now the tobacco industry is confident of winning its case in the UK.