Modular subsea manifold system

A modular manifold system for connection to a header pipe, comprising: a central hub 12 comprising a header pipe connection, the header pipe connection defining a flow port permitting fluid communication between a header pipe and the central hub; a conduit connection arrangement located on the central hub, for connection of a conduit thereto and defining a flow port permitting fluid communication between the central hub and a connected conduit; a module connection arrangement located on the central hub, the module connection arrangement defining a flow port permitting fluid communication between the central hub and a connected module. Aspects relate to a method for installing a modular manifold system on a header pipe. Embodiments include a subsea conduit, comprising: a plurality of modules distributed therealong, each module comprising: a valve therein and a valve actuation arrangement; a fluid port; a connection arrangement for connection of a secondary component thereto; wherein the secondary component is configurable to receive a fluid flow from the fluid port, and the valve is operable to selectively restrict fluid flow through at least one of the subsea conduit and the fluid port.