Isn't Ashcroft still a tax exile despite his promises to become UK domiciled? I would happily see a penalty imposed on him to fulfil any such obligations.
You may well be right about his tax status, but Ashcroft is an asset to the country. One example I can quote is his donation of £5m to the Imperial War Museum to set up the Extraordinary Heroes Gallery which displays Ashcroft's collection of Victoria Crosses and George Crosses, by far the biggest in the world.
Start penalising him and he could well take his ball and go and play somewhere else, which would deprive the IWM of a fantastic asset.