A turbine engine comprising: a housing; a rotor; a bearing seal assembly; an oil compartment containing oil on one side of the seal assembly; an air compartment containing air on another side of the seal assembly; said bearing seal assembly comprising: a first circumferential seal between the oil compartment and the air compartment and providing a seal between the housing and the rotor; a second circumferential seal between the air compartment and the first circumferential seal and providing a seal between the housing and the rotor, the second circumferential seal defining a fluid compartment of elevated pressure between the first circumferential seal and the second circumferential seal; and a backup circumferential seal providing a seal between the housing and the rotor and adjacent one of the second circumferential seal and the first circumferential seal; wherein said backup circumferential seal provides a less effective seal between the housing and the rotor than that provided by said first and second circumferential seals (54, 56); characterised in that: the bearing seal assembly is provided between a bracket radially outwardly of the bearing seal assembly and the rotor radially inwardly of the bearing seal assembly, and is axially fixed between a snap ring on the oil side of the seal assembly and a snap ring and an anti-rotation piece on the air side of the seal assembly. a housing; a rotor; a bearing seal assembly; an oil compartment containing oil on one side of the seal assembly; an air compartment containing air on another side of the seal assembly; said bearing seal assembly comprising: a first circumferential seal between the oil compartment and the air compartment and providing a seal between the housing and the rotor; a second circumferential seal between the air compartment and the first circumferential seal and providing a seal between the housing and the rotor, the second circumferential seal defining a fluid compartment of elevated pressure between the first circumferential seal and the second circumferential seal; and a backup circumferential seal providing a seal between the housing and the rotor and adjacent one of the second circumferential seal and the first circumferential seal; wherein said backup circumferential seal provides a less effective seal between the housing and the rotor than that provided by said first and second circumferential seals (54, 56); characterised in that: a first circumferential seal between the oil compartment and the air compartment and providing a seal between the housing and the rotor; a second circumferential seal between the air compartment and the first circumferential seal and providing a seal between the housing and the rotor, the second circumferential seal defining a fluid compartment of elevated pressure between the first circumferential seal and the second circumferential seal; and a backup circumferential seal providing a seal between the housing and the rotor and adjacent one of the second circumferential seal and the first circumferential seal; wherein said backup circumferential seal provides a less effective seal between the housing and the rotor than that provided by said first and second circumferential seals (54, 56); characterised in that: the bearing seal assembly is provided between a bracket radially outwardly of the bearing seal assembly and the rotor radially inwardly of the bearing seal assembly, and is axially fixed between a snap ring on the oil side of the seal assembly and a snap ring and an anti-rotation piece on the air side of the seal assembly.