A gas turbine engine comprising at least one drum pack having two or more annular discs 62a-c. Adjacent discs 62a-c are connected by drive arms 68 the drum pack is provided with a tubular sealing body 84 positioned radially inwards of the drive arms 68 and extending from a first disc 62a to a last disc 62c in the drum pack. The first 62a and last 62c discs have the greatest axial separation of all discs 62a-c in the drum pack. The sealing body 84 engaging the first 62a and last 62c discs and the engagement being arranged to limit or prevent the ingress of liquid into a drum cavity 76 defined between the first 62a and last 62c discs, the drive arms 68 and the sealing body 84.