When do you use RPI to measure inflation and when do you use CPI? The answer is quite simply "whenever we feel like it!". In a response earlier this month to a petition to change the student loan interest rate from being linked to RPI to CPI to reflect the government's inflation figures, the Prime Minister's office has stated it has no intention to change a thing...in line with the general policy of taking in to account public opinion through the site.

The Consumer Prices Index (CPI), which excludes mortgage repayments, is currently lower then RPI, but this will not necessarily always be the case. We believe it is right to use the same measure of inflation consistently across the years, and not to make changes simply because one measure is lower (or higher) at a particular point in time.

As far as I'm concerned the argument put up by the Prime Minister's office is fairly wishy washy. It claims that RPI is still a measure of inflation and it's the one that's always been used. They believe that it's not correct to change the goalposts and to stay consistent...except of course when it comes to measuring inflation that you announce to the public and then you can change between RPI and CPI measures as and when it best serves the headlines.

What is most important for graduates managing their finances is consistency and certainty about the rate they will be charged and the volatility of UK inflation since 1997 has been around one sixth of that in the previous two decades. The interest rate on student loans has averaged out at below 3% per annum.

The government here argue that because currently inflation doesn't fluctuate wildly, an analysis highly subjective given the real levels of change in the last decade, the rates should not be compared to the much more stable CPI in the future. It's an argument that manages to shoot itself in it's own foot given that you cannot argue stability as a reason for keeping with one method when there is a more stable method.

or the vast majority of borrowers - those who took the new income contingent student loans available since 1998 - the revised interest rate does not affect the level of the borrower's monthly repayments. These are set solely in relation to their earnings - at 9% of all earnings above £15,000.

And then the final strategy in this response, a strategy that starts with hypocritically arguing historical practice before moving to false arguments of stability, is to muddy the water with an irrelevant fact. What does it matter if the rate you are paying stays the same if the rate you are being charged in interest doesn't? Yes you certainly make the same repayments with a 3% inflation or a 10% inflation, but the impact of that repayment then varies.

I'm not going to get in to the arguments over which is the most appropriate measure of inflation, though increased feelings of people feeling tighter budgets do suggest that our average pay rises of 3-4% in this country are actually less than the inflation rate, but how can a government response be taken seriously when they try to spin their answer without any regard to the inherent hypocrisy and bare faced cheek of what they're saying in the process?