Mr Whittam Smith's appointment is expected to be announced on Thursday by Jack Straw, the Home Secretary, who has blocked the promotion of Lord Birkett, 68, one of two BBFC vice-presidents, to succeed Lord Harewood, the retiring president.
The board has been lambasted for a series of decisions, including the awarding of an 18 certificate to the feature film Crash, which linked sexual gratification to car accidents.
Mr Straw is said to have lost patience with the BBFC after finding out last summer that guidelines on the classification of sex videos had been unilaterally relaxed. This meant that videos that customs officers would normally seize were freely available in rental shops.
The first task facing Mr Whittam Smith will be to find a successor to James Ferman, the controversial American-born director who is retiring after 22 years.
The revamped board is set to undergo a change in culture, moving away from the secrecy that has traditionally surrounded its decisions to become more accountable to ministers and the general public.
Mr Straw's refusal to endorse the promotion of Lord Birkett came as a surprise. Home secretaries have the right to veto appointments to the board, a private body funded by the film industry, but internal candidates are usually rubberstamped.Reuse content