Up until the 1908 Act allotment plots were normally 20 rods (or poles) and ranged from this one eighth of an acre to 4 acres in size (i.e. 640 rods/poles). The 1908 Act led to these smaller plot sizes to differentiate them from smallholdings.

Plot sizes are measured in rods, an old Anglo-Saxon unit so-called because it was the length of the rod used to control a team of eight oxen.

A rod is 5.5 yards (5.03 metres).

1 pole = 1 rod = 1 perch = 16 ½ feet.

A chain = 4 rods = 22yd (20.12m) and is the length of a cricket pitch.

A furlong = 10 chains.   A mile = 8 furlongs.

An acre is the area of land that could be ploughed in a day, being a furrow long (furlong)and a chain wide, or 160 square rods.

So in 1908 the standard size for an allotment became 10 rods

A 10 rod allotment is 10 square rods in area, 10 x 5.5 x 5.5 = 302.5 sq yd (253 sq m).

In metric units, a 10 rod allotment is one fortieth of a hectare: in imperial units it is one sixteenth of an acre.

Of course, the principle behind the average plot size no longer holds water, so local authorities, faced with a legal obligation to provide allotments and with lengthy waiting lists in some areas, have halved the traditional 10 rod plots to 5 - an area of 151.25 sq yards, or 126.5 sqm.  There are even reports that a London council have reduced some plots, available to novice gardeners, to 1.5 rods; and this is bound to cause problems with crop rotation as well as increasing the rist of pest and disease infestation for neighbouring allotments.