Conservative Party Chairman Oliver Dowden this morning resigned declaring “somebody must take responsibility”.

Yet it is far from clear that blame for the two overnight defeats in two very different sets of electoral circumstances could ever be laid at the door of the mild-mannered Mr Dowden.

The voters of Tiverton were not demanding his head as the price of shunning the Liberal Democrats.

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Labour would have won Wakefield had somebody else been filling that position.

So why has he gone?

Mr Dowden has been on the frontline across the country, perhaps more than any other cabinet minister.

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Although his letter was scrupulously polite, the implication is that there has been a failure of anyone to take full responsibility.

The person whose name comes up on the doorstep more than any other – as new Tiverton MP Richard Foord made clear in his speech – is Boris Johnson.

It is hard not to see Mr Dowden as pointing the finger at the prime minister and duly departing the stage, although he stopped short of unsheathing his dagger.

Mr Dowden has increasingly been seen as something of a Boris Johnson sceptic and the veteran backroom fixer turned cabinet minister has seen enough highs and lows in the Conservative Party to know what true warning signals look like.

Having been one of the first high profile figures to back Mr Johnson for the leadership, he has been giving the impression of falling out of love with him.

There are some signs this has been reciprocated.

Under a month ago newspaper stories surfaced suggesting Mr Dowden could be demoted for previous by-election failures and handed a more junior government job.

In the event, he has decided to jump, perhaps before he was pushed.

The big question is whether there will be others.

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This is a cabinet occasionally taunted for the way they are made to defend all manner of escapades, indiscretions and tangles with little sign that any have obvious limits to what they will stand by when facing interviewers.

Loyalty in the most difficult situations is rewarded above other characteristics so it is no surprise there is not the same-sized list of people willing to jump ship that you might have been able to draw up when Theresa May was prime minister.

So while not impossible, it is not clear who would be next and when they would take action.

However much Tory MPs tell themselves they expected the double by-election defeat, the scale of the loss in Tiverton ought to prompt serious reflection.

It means no Conservative seat can be described as safe.

The scale of anti-Tory tactical voting which meant Labour lost its deposit in Tiverton is another flashing red warning indicator.

And now the departure of Mr Dowden, who until recently was seen as the loyalists’ loyalist, is another sign of the shift.

It is not clear there is widespread appetite for sudden change given that question has been mulled over so much in recent weeks and months.

However, bit by bit, all the bad news is a poison dripping into the Tory bloodstream.

The effects of that will take time to show.