Recently a test was carried out to examine the virtues of Sodium Thiopental as a truth serum, using MPs as test subjects.
"Sadly" said Dr Misnomer of the Westminster Brains Trust, "the tests have proven to be a complete waste of time due to the fact that MPs are simply unable to answer any question posed to them".
When asked if they think they chose the wrong subject group, Dr Misnomer admitted that when they asked an (un-named) MP if he would be willing to take part in a study of the effectiveness of truth serums, the reply was "Well, it's not so much a matter of whether I am willing or not, nor indeed whether or not truth serums may or may not work. For a start, if I were to volunteer, and that is not to say that I will, or would, there are many greater things that we in the shadow cabinet are working on, and THAT is the truth. Less it be said that we in the Labour party might stand in the way of scientific advancement were I to decline, I can assure you that since the coalition have been in power, we have seen no fix to the economy. So in essence, to answer your question, any sort of volunteer programme to test such a substance would need to be put to parliament, where......"
At this point, the effectiveness of chloroform was effectively proven.
As a final word on the matter, Dr Misnomer did mutter that "...even if politicians were able to answer a simple question, there is no foundation data to know if they are telling the truth or lying anyway. I don't think we will ever know..."