Professor Michael McMahon:

Shocks can occur to the point at which it suddenly becomes really difficult or costly to be able to pass through €1 billion, €2 billion, or whatever it is in extra funding. From a budgetary perspective, which is where we have the expertise, that is not a very good way of budgeting. It is absolutely normal that budgets might be off and we should expect them to be off. Sometimes a bit too much is allocated and sometimes a bit too little is allocated. Yet, we would not be able to call it good budgeting when there are repeated, one-way errors that build in a predictable fashion.