The idea of installing an interim leader to steer the Labour party through the next couple of years of this parliament is one of those superficially attractive proposals currently doing the rounds. “Why rush”, goes the argument, “in selecting a leader? Why not pause and reflect. Install someone for a couple of years while the party does its soul-searching and comes up with the right answer.”

The Guardian is the latest to float the suggestion in an editorial column yesterday, urging the party to avoid rushing into a decision by having Alan Johnson lead the party until 2017. Labour should “think, discuss and choose, in that order,” it says.

The excellent Conor Pope at LabourList has already pointed out that holding off for a couple of years would simply “extend the leadership contest into 2017, not postpone it until then”. Yet there is a precedent for having two leaders in a parliament and things working out well. Two precedents, in fact.

Both of Labour’s most electorally successful leaders, Harold Wilson and Tony Blair, took over mid-parliament. In both cases it was due to the untimely deaths of their predecessors. The shock of the new and the sudden release of momentum a new leader brings were telling in both cases. Wilson won in 1964 and Blair in 1997.

But here’s the obvious flaw. The deaths of Hugh Gaitskell in 1963 and John Smith in 1994 were, of course, completely unexpected. What the Guardian is talking about is diarising a change of leader in two years’ time. Rather than providing Labour with a mid-parliament fillip, it would simply unleash a destructive and unseemly bun-fight over the succession. The inevitability of a leadership contest would see rival front benchers show-ponying in their roles for two years and ratchet up Labour’s already poisonous addiction to internal plotting as leadership campaigns were assembled at the margins. The talk would be of nothing else, never mind the deal-making, intrigue and backbiting. The party would be paralysed.

This aside, a temporary leader would make formulating strategy and policy nigh on impossible. Presumably they would have been put in place without the involvement of ordinary members, and would therefore lack the legitimacy to do anything other than mind the shop. It’s all very well shelving a decision about whether rail nationalisation should be in the next manifesto, until the appointment of the permanent leader, but what would happen if there was a vote on committing troops to a conflict? How would the interim leader respond to big, emerging issues if it was clear a large minority of the party felt differently?

Then there’s the problem that they might not want to leave. Indeed, what if they were deemed to be more popular than the alternatives? The complaint from rivals would be that they had unfairly used incumbency for their own advantage. Cue the dust up of all dust-ups.

But the whole idea of an interim leader rests upon the proposition that being in opposition is inherently wasted time. Shorn of executive power, frontbench roles are not worth Lyndon Johnson’s pitcher of warm spit. This is dangerously naïve. Sharp and persistent shadow ministers force real ministers to do things they don’t want to do and stop them doing some things they would like to.

A good opposition can still influence the political agenda. How much of David Cameron’s rash election pledge to spend an additional £8 billion on the NHS was down to Andy Burnham’s relentless onslaught at the government’s costly NHS reorganisation?

Indeed, a strong and effective frontbench is essential to the functioning of government. Labour politicians need to be fully committed to fulfilling their roles in scrutinising legislation and making alternative arguments. They should not be off-stage plotting. The last thing the Labour party needs is two years of indolence and introspection. It cannot afford an interregnum while it undergoes the political equivalent of psychoanalysis. No, what the party needs instead is a dose of cognitive behavioural therapy.

Accept what went wrong. Fix it. Learn from it. Choose a new leader. Get on with it.