Very prone to aphid infestation, usually greenfly. Might be easier to invest in a systemic rather than a contact insectide, which will keep them clear for a week or so, depending on the product. Soapy water is just a contact treatment, and if you use it every day, depending on the soap you've used, that's not too healthy either in the garden.

There is a Lupin aphid - once the poor plant has that, there isn't much you can do. As Bamboo said, try an insecticide but sadly you may have to cut that plant back and let it regrow.

Lupin aphids are large and grey and pretty disgusting to squash. You can save the plant if you are vigilant and squash them as they appear.