<p>A seal for use in replacing an existing fluid-carrying pipe with a replacement pipe comprises a tubular body of a flexible material, the body having a rear portion (52) for connection to the leading end of the replacement pipe and front portion (54) adapted in use to provide a barrier to the flow of fluid along the annular gap between the internal wall of the existing pipe and the external wall of the replacement pipe, the seal also having a membrane (62) serving to prevent the flow of fluid through the bore of the seal, the membrane being puncturable or removable to permit the flow of fluid through the seal. <IMAGE></p>
