THE exchanges during Prime Minister's Questions this week were quickly buried beneath Gordon Brown's bulldozing and bullish statement on the health of the economy, but they were nonetheless important and instructive. Mr Howard asked each of his six questions about a rather obscure radio commerical encouraging youngsters to make enquiries about new arrangements for university fees; he suggested that the government was breaking its own rules (which he quoted in full) by spending public money on advertising policies which had not been approved by parliament and become law in other words, using public money for party political advantage. Mr Blair clearly did not know anything about the commercial but, instead of admitting as much and saying he would look into the matter, he chose to ignore the questions and instead deliver a passionate defence of the top-up fees proposal. As Mr Howard repeated the question, with variations, five times Mr Blair became more and more excited about the contrast between the merits of his proposals and the triviality of Mr Howard's interrogation. BUT beneath this question lies an extremely important and sensitive issue. Since 1945 rules on the distinction between spending public money on publicity about what the government intends to do and actually has done have been carefully observed and safeguarded: only when Parliament had approved an authorising Bill could public money be spent on publicising it. When Labour came in to power in 1997 Alastair Campbell set about demolishing the security fences between party and official publicity in many ways and it is disappointing to discover, apparently, that his departure has not stopped the rot. Mr Howard was right to ask the question and the Prime Minister should have shown more respect for the principle behind it.