A joint assembly for connecting a first pipe having a first inner diameter and a second pipe having a second inner diameter which is larger than the first inner diameter, the joint assembly comprising: an annular section comprising an annular wall defining a flow path through the annular section and configured to connect to the first pipe and to mate with the second pipe; and a clamp portion configured to clamp the second pipe between an outer surface of the annular section and an inner surface of the clamp portion; wherein an inner diameter of the annular section varies in a gradual manner from a first inner diameter at a first end of the annular section to a second inner diameter at a second end of the annular section; the first inner diameter of the annular section is substantially equal to the inner diameter of the first pipe; the second inner diameter of the annular section is substantially equal to the inner diameter of the second pipe; an inner surface of the annular section is tapered between the first end of the annular section and the second end of the annular section; and the annular section is thicker at the first end of the annular section than at the second end of the annular section; characterised in that an outer surface of the annular section has a stepped arced profile, comprising a first arc having a first radius adjacent the first end and a second arc having a second radius adjacent the second end, with a transition portion therebetween. an annular section comprising an annular wall defining a flow path through the annular section and configured to connect to the first pipe and to mate with the second pipe; and a clamp portion configured to clamp the second pipe between an outer surface of the annular section and an inner surface of the clamp portion; wherein an inner diameter of the annular section varies in a gradual manner from a first inner diameter at a first end of the annular section to a second inner diameter at a second end of the annular section; the first inner diameter of the annular section is substantially equal to the inner diameter of the first pipe; the second inner diameter of the annular section is substantially equal to the inner diameter of the second pipe; an inner surface of the annular section is tapered between the first end of the annular section and the second end of the annular section; and the annular section is thicker at the first end of the annular section than at the second end of the annular section; an inner diameter of the annular section varies in a gradual manner from a first inner diameter at a first end of the annular section to a second inner diameter at a second end of the annular section; the first inner diameter of the annular section is substantially equal to the inner diameter of the first pipe; the second inner diameter of the annular section is substantially equal to the inner diameter of the second pipe; an inner surface of the annular section is tapered between the first end of the annular section and the second end of the annular section; and the annular section is thicker at the first end of the annular section than at the second end of the annular section; characterised in that an outer surface of the annular section has a stepped arced profile, comprising a first arc having a first radius adjacent the first end and a second arc having a second radius adjacent the second end, with a transition portion therebetween.