Mervyn King is one smart guy and that has always been abundantly clear. Unfortunately, it is his thirst for power and influence that has clouded his judgment one too many times. He has now committed the unforgivable sin of compromising the independence of the Bank of England by involving himself in the economic policy of the coalition. He is expected to be politically neutral but has shown himself to be politically biased and as a result is now in an untenable position. King must go.

During my time on the Monetary Policy Committee (MPC), King made it abundantly clear that members should not comment on fiscal policy and should stay out of party political matters. He has failed to follow his own advice. How could Ed Miliband or Alan Johnson ever trust King to give them advice on economic policy, now he has shown his true party political colours? Once independence has been compromised it can never be restored.

There was so much in those leaked diplomatic cables, though, that made sense, much of which will be highly embarrassing to the government.

King confirmed my long-standing view that on economic policy the coalition is totally out of its depth. In a devastating critique he told US ambassador Louis Susman that David Cameron and George Osborne lacked experience, dealt in broad generalities, tended to think about issues only in terms of their political rather than their economic impact and surrounded themselves with a very narrow and weak team of young advisors. That is a recipe for bad economic policy making.

Other information emerged showing that the ever acerbic Tory party deputy chairman and member of the Treasury select committee, Michael Fallon, also has little confidence in Osborne's economic leadership.

The governor pointed out that both Cameron and Osborne have failed to grasp the pressures they will face when attempting to cut back on spending, when "hundreds of government officials will make pleas of why their budgets should not be reduced". This is essentially the same view taken by my ex-MPC colleagues and Rachel Lomax and John Gieve who recently both questioned the government's ability to deliver their planned cuts.

There were insights, though, in the embassy documents that I found truly shocking, not least the details of King's attempts to co-author the coalition's strategy on the deficit. That is definitely not part of his job description.

And this information emerged only a few days after revelations by Adam Posen at the Treasury select committee that members of the MPC were uncomfortable that statements King had made were overly political. The Financial Times, in a recent article, made it clear that others on the staff at the Bank shared that view. The governor of the Bank of England should not be in the business of shaping one political party's macro-economic policy.

Mervyn King should consider his position. It's time for a change at the top at the Old Lady of Threadneedle Street.