A useful summary measure of whether the MPC is on track to meet the 2% inflation target is the Bank of England's mean projection two years ahead based on unchanged policy. In the February Inflation Report, this stood at 2.48%, representing the largest positive deviation from the target since February 1998 and clearly signalling the need for higher interest rates – see chart.

MPC doves, led by the Bank's Governor Mervyn King, have used two subterfuges to deflect media and market attention away from this glaring inconsistency. The first is to refer to the central or modal projection rather than the mean forecast. The central projection two years ahead assuming unchanged policy was 2.08% in February. The mean forecast also takes account of the skew of risks – judged to be weighted strongly to the upside currently. The inflation-targeting remit implies that the MPC should be equally concerned about over- and undershoots and it is reasonable to place greater weight on avoiding large deviations, in which case the mean forecast is the correct focus of policy.

The second trick is to refer to the forecast based on market interest rate expectations rather than unchanged policy. This allows the doves to take credit for market-implied tightening without ever delivering. In February, for example, the central and mean forecasts two years ahead incorporating the market interest rate path were 1.62% and 2.02% respectively. This, however, assumed an average Bank rate of 0.7% in the second quarter, implying a quarter-point rate hike in April or May – most economists expect continued inaction next month. In this way, the MPC can repeatedly push back the start date of tightening while claiming that policy is still consistent with the target, based on later significant interest rate rises discounted by the money market curve.

Also convenient for the Governor's "news management" is the convention of releasing the forecast numbers a week after publication of the Inflation Report. The central projection is more readily estimated from the Report's fan charts than the risk-adjusted mean. Journalists at the February press conference struggling to absorb a large volume of information understandably failed to spot the large overshoot of the mean forecast, enabling the Governor to escape difficult questioning on how this could be reconciled with unchanged policy. The caravan had moved on by the time the numbers barked a week later.

While these presentational tricks provide useful wriggle room, the doves can, of course, simply enforce a change in the forecast to suit their policy prescription, since the forecasting process is almost completely opaque and reliant on "judgement". The two-year-ahead projection, for example, was cut between May and August last year without credible justification as the doves sought to lay the foundation for a further expansion of QE, following the US lead given by their soul-mate Professor Bernanke. Reality – in the form of much higher inflation than the August Report projected – intervened to stymie these plans.

Will such an ad hoc downward adjustment be used to justify a further delay in raising rates at the May MPC meeting? As of yesterday, sterling's effective rate was 1.5% below the starting level assumed in the February Inflation Report while energy prices were significantly higher, factors arguing for an upward inflation revision. The doves, however, may resort to their favoured if tarnished "output gap" defence if next week's preliminary GDP release shows a smaller first-quarter rise than the 0.6-1.0% apparently factored into the February forecast (although business surveys and labour market trends suggest that official output statistics understate recent economic performance).

The opacity of the forecasting process and scope for creative interpretation of the remit and presentational manipulation imply that there is no effective constraint on the MPC's "discretion". Inflation-targeting has become meaningless.