In an actual transformer, there is primary leakage flux as well as secondary leakage flux. The primary leakage flux is the flux which links with the primary but not with the secondary. Similarly, the secondary leakage flux is the flux which links with the secondary but not with the primary winding. Since, leakage flux links with only one winding. It produces an induced e.m.f. in that winding. It is therefore, equivalent to a small inductance in series with the winding.