Who decides if the answer is meaningful?

The ability of the Government to avoid answering questions in Parliament never ceases to amaze me. What esepcially amazes me is the skill with which such avoidances occur. There is of course the classic "disproportionate cost" line, and if in doubt they can just ignore the question completely and asnwer a different one. Today though I have come across what is quite possibly the best response ever.

The Tory MP for South West Hertforshire, David Gauke, asked David Lammy what percentage of the current (and proposed) computer systems in the Department of Culture, Media and Sport use Open Source software. Lammy, (also known as Minister for Nationalising Old Things) said

"It would not be meaningful to provide an answer in percentage terms as my Department uses open source software mainly on backend systems which in themselves only make up a small percentage of total computer systems but which can be potentially accessed by a high percentage of staff.

Surely it is not for the person answering a question to ascertain whether that answer is meanigful or not? Lammy argument is essentially that the percentage would look very low, when the actual usage of the system is quite high. However, why not just give the percentage with that caveat and be done with it if that is the case?

For anyone wondering, Lammy did go on to say that the Open Source software used in DCMS includes Linux, MySql and Firefox. The two former probably being the back office system and the former replacing IE on expensive Microsoft Windows systems. He went on to say aswell that DCMS would continue to use Open Source"where it makes business and economic sense to do so". In other words, where we havn't asked Microsoft for an opinion.