According to various sources online, including The Guardian, Banished had over 3.4 million viwers for last night's episode. 

Jimmy McGovern’s penal colony drama Banished starring Russell Tovey began with more than 3 million viewers, giving BBC2 a rare ratings victory over both BBC1 and ITV. The drama about the first fleet of convicts transported to Australia from Britain and Ireland launched with 3.4 million viewers, a 16.2% share of the audience from 9pm on Thursday. Banished, co-produced by the makers of The King’s Speech and another BBC2 drama, Top of the Lake, would have been BBC2’s biggest new drama launch for several years, had it not been for the success of Wolf Hall, which began in January with an overnight audience of 3.9 million (16.5%).