A multi-charge ignition system including a spark plug control unit and at least two coil stages, said spark plug control unit being configured to control said at least two coil stages so as to successively energise and de-energise said coil stage(s) to provide a current to a spark plug, wherein said two stages comprise: a first transformer (T1) including a first primary winding (L1) inductively coupled to a first secondary winding (L2); a second transformer (T2) including a second primary winding (L3) inductively coupled to a second secondary winding (L4); the high sides of the first and secondary primary windings being connected to a common energizing potential; wherein said multi-charge ignition system further comprises: a first switch (M1) is electrically connected between a power supply high side and the high side of the first primary winding, a second switch (Q1) is electrically connected between the low side of the first primary winding (L1) and the power supply low side supply/earth, a third switch (M3) is connected between the junction of the first switch (M1) and the high side end of the first primary winding (L1) and a point between the low side of the second primary winding (L3) and low side supply/earth, and further including a fourth switch (Q2) located between the low side of the second primary winding (L3) and said point, and a fifth switch (M2) located between said point and low side supply/earth. a first transformer (T1) including a first primary winding (L1) inductively coupled to a first secondary winding (L2); a second transformer (T2) including a second primary winding (L3) inductively coupled to a second secondary winding (L4); the high sides of the first and secondary primary windings being connected to a common energizing potential; wherein said multi-charge ignition system further comprises: a first switch (M1) is electrically connected between a power supply high side and the high side of the first primary winding, a second switch (Q1) is electrically connected between the low side of the first primary winding (L1) and the power supply low side supply/earth, a third switch (M3) is connected between the junction of the first switch (M1) and the high side end of the first primary winding (L1) and a point between the low side of the second primary winding (L3) and low side supply/earth, and further including a fourth switch (Q2) located between the low side of the second primary winding (L3) and said point, and a fifth switch (M2) located between said point and low side supply/earth. a first switch (M1) is electrically connected between a power supply high side and the high side of the first primary winding, a second switch (Q1) is electrically connected between the low side of the first primary winding (L1) and the power supply low side supply/earth, a third switch (M3) is connected between the junction of the first switch (M1) and the high side end of the first primary winding (L1) and a point between the low side of the second primary winding (L3) and low side supply/earth, and further including a fourth switch (Q2) located between the low side of the second primary winding (L3) and said point, and a fifth switch (M2) located between said point and low side supply/earth. <EOS>