Could you explain the difference between the size of the budget deficit,which relates to full employment ?.

Why does reduced company tax contribute to full employment? All other things being equal, if a company is paying more tax, the government is receiving it and presumably spending it, which contributes to employment rates. If it isn't taxed, then either the company or the shareholders are receiving and then spending it, contributing to full employment. So long as tax rates don't make companies export potentials uncompetitive corporate tax should make no discernible difference to employment. It is merely a change to where that money is being spent.