Mashed Potato

I made a Jamie Oliver Fish Pie when my brother and his wife came over for dinner at the weekend.

My rude little brother commented that the mashed potato topping was 'hard'. I have to admit it wasn't all that good. I probably had not mashed the spuds for long enough due to an aching wrist. Not only that but I did not add the ' few sploshes' of olive oil that Jamie Oliver recommended, for health reasons.

I would like advice on how to make delicious fluffy mashed potato without adding lots of butter or oil. I am thinking of buying a hand-held food mixer and trying that.