A drainage system (100, 1300) configured to be buried in a permeable ground layer, the system comprising: a tubular cap (102, 1302) that comprises an end wall and one or more curved sidewalls that extend from a perimeter of the end wall in the form of a skirt to define a recess (526, 1326) within the cap (102, 1302); a tubular body (104, 1304) comprising: an inlet (214, 1314) at a first end (212, 1312) of the body (104, 1304), receivable within the recess (526, 1326) of the cap (102, 1302); an outlet at a second end of the body; and a passage (210, 1310) to allow fluid flow from the inlet (214, 1314) to the outlet; the system further comprising a spacer arrangement (106, 1306) comprising a mounting portion that extends from within the cap (102, 1302), the mounting portion configured to be received within the passage (210, 1310) at the first inlet (214, 1314) end of the body (104, 1304) such that, when the inlet (214, 1314) is received in the recess (526, 1326) of the cap (102, 1302), the mounting portion locates within the passage (210, 1310) at the first inlet (214, 1314) end to mount the cap (102, 1302) to the body (104, 1304), the spacer arrangement (106, 1306) being further configured to space said one or more sidewalls of the cap (102, 1302) from the body (104, 1304) such that, when the inlet (214, 1314) is received in the recess (526, 1326) of the cap (102, 1302), a channel is formed between an inner surface of said one or more sidewalls of the cap (102, 1302) and an outer surface of the body (104, 704, 1304), whereby fluid is able to flow through the channel to the inlet (214, 1314) at the first end of the body (104, 704, 1304). a tubular cap (102, 1302) that comprises an end wall and one or more curved sidewalls that extend from a perimeter of the end wall in the form of a skirt to define a recess (526, 1326) within the cap (102, 1302); a tubular body (104, 1304) comprising: an inlet (214, 1314) at a first end (212, 1312) of the body (104, 1304), receivable within the recess (526, 1326) of the cap (102, 1302); an outlet at a second end of the body; and a passage (210, 1310) to allow fluid flow from the inlet (214, 1314) to the outlet; the system further comprising a spacer arrangement (106, 1306) comprising a mounting portion that extends from within the cap (102, 1302), the mounting portion configured to be received within the passage (210, 1310) at the first inlet (214, 1314) end of the body (104, 1304) such that, when the inlet (214, 1314) is received in the recess (526, 1326) of the cap (102, 1302), the mounting portion locates within the passage (210, 1310) at the first inlet (214, 1314) end to mount the cap (102, 1302) to the body (104, 1304), the spacer arrangement (106, 1306) being further configured to space said one or more sidewalls of the cap (102, 1302) from the body (104, 1304) such that, when the inlet (214, 1314) is received in the recess (526, 1326) of the cap (102, 1302), a channel is formed between an inner surface of said one or more sidewalls of the cap (102, 1302) and an outer surface of the body (104, 704, 1304), whereby fluid is able to flow through the channel to the inlet (214, 1314) at the first end of the body (104, 704, 1304). an inlet (214, 1314) at a first end (212, 1312) of the body (104, 1304), receivable within the recess (526, 1326) of the cap (102, 1302); an outlet at a second end of the body; and a passage (210, 1310) to allow fluid flow from the inlet (214, 1314) to the outlet; the system further comprising a spacer arrangement (106, 1306) comprising a mounting portion that extends from within the cap (102, 1302), the mounting portion configured to be received within the passage (210, 1310) at the first inlet (214, 1314) end of the body (104, 1304) such that, when the inlet (214, 1314) is received in the recess (526, 1326) of the cap (102, 1302), the mounting portion locates within the passage (210, 1310) at the first inlet (214, 1314) end to mount the cap (102, 1302) to the body (104, 1304), the spacer arrangement (106, 1306) being further configured to space said one or more sidewalls of the cap (102, 1302) from the body (104, 1304) such that, when the inlet (214, 1314) is received in the recess (526, 1326) of the cap (102, 1302), a channel is formed between an inner surface of said one or more sidewalls of the cap (102, 1302) and an outer surface of the body (104, 704, 1304), whereby fluid is able to flow through the channel to the inlet (214, 1314) at the first end of the body (104, 704, 1304).