The flaw in the Daily Mail article is that they assume that all the businesses would still be able to operate without the illegal workers. We know that the Daily Mail would oppose giving the workers legal status so that they could pay taxes, so you have to wonder what their point is.
It has to be said though that it certainly makes a change for the Daily Mail to complain about illegal immigrants engaged in employment. Their usual approach is to accuse immigrants (both legal and illegal) of coming here to live on benefits and fleece the british taxpayer which is obviously nonsense. The reason people emigrate is to earn a living not to live on paltry state benefits.
Of course the Daily Mail has a long history of hating immigrants. They were opposed to Jewish refugees coming to the UK in the 1930s and they were responsible for the notorious “Hooray for Mr Hitler” headline.