Queen Mary Library Services have a free 30 day trial to the Bibliography of British and Irish History. This provides bibliographic data on historical writing dealing with the British Isles, and within the British Empire and Commonwealth, from 55BC to the present.
It is the successor to the Royal Historical Society Bibliography of British and Irish History, which was freely available online from 2002 to 2009. It is now published by Brepols.
To use the trial go to: www.brepolis.net, choose Enter databases and then choose BBIH, which is the only available option.