I think the point is that if you've got a margin of £1bn, you can invest a few million in security and it not be a problem. If you've got a margin of £1m, that security investment is significantly more expensive.
I think the point is that if you've got a margin of £1bn, you can invest a few million in security and it not be a problem. If you've got a margin of £1m, that security investment is significantly more expensive.