When I heard that Dr Dan Poulter had switched from the Conservatives to Labour on Saturday afternoon I felt totally gobsmacked - but not completely surprised.
I had a feeling, which I'd shared with colleagues, that he might not contest this year's General Election in his Central Suffolk and North Ipswich seat.
He'd always been a moderate One Nation Tory - out of step with the more raucous right-wing mood that seems to be increasingly dominating that party.
And after working as a part-time psychiatrist in a London hospital for several years he has recently moved to a similar role for the Norfolk and Suffolk Foundation Trust based at Ipswich Hospital.
It's already sparked comment about a potential conflict of interest particularly as the NSFT has been at the eye of a storm for several years with many MPs, including Dr Poulter expressing concerns about its services.
So I was not at all surprised by the element of his announcement on Saturday that he would not be standing for re-election in the General Election.
The prospect of being part of a pretty small rump of Tory MPs, many of whom do not share your outlook on the world, cannot have been very attractive when you've got a part-time job you care about and you could do full-time.
But I hadn't foreseen that he might jump ship to Labour before the end of the parliament - although perhaps that should not have come as such a shock.
In 2021 he told former Labour MP Gloria del Piero, in a television interview, that he had voted for Tony Blair in 2001 and 2005 before being attracted back to the Conservatives by David Cameron's "inclusive" policies.
I've come to know Dr Poulter quite well over the last 15 years since he was first adopted as candidate for the constituency in 2009, a year before he won the seat.
In private conversations - and in some public statements - I know that he has become increasingly concerned about the government's attitude to the NHS.
The short period of Suffolk Coastal MP Therese Coffey's spell as Liz Truss's Secretary of State for Health was a particular concern for him.
He said he feared her objections to the "nanny state" threatened public health campaigns that aimed to ensure people were less likely to need hospital treatment.
From that point of view, it is unlikely that Dr Coffey's criticism of him after his switch this week will cause him undue concern.
What remains to be seen is whether Dr Poulter will continue in any public role after he has returned to full-time medicine as a career.
He's made it quite clear that will be his full-time job, but has also indicated he would like to be able to help an incoming Labour government develop health policy - particularly in regard to mental health services.
That has led some to question whether Labour may have offered Dr Poulter a peerage after he stands down from the House of Commons - a suggestion both sides have firmly denied.
What is an issue now, for the last few months of this parliament, is how Dr Poulter's office operates - MPs offices are generally staffed by people who share his or her political view of the world.
Dr Poulter's staff are mainly Conservatives while he is now a Labour MP. While that does not cause an issue with most constituency casework, there are occasions when there could be difficulties.
However the simple fact is this situation isn't going to last long. The next election is likely to be held in October or November.
That means the current parliament is set to be dissolved in September or early October - and with the summer recess in between the current situation will not have to carry on too long.
But these are unchartered waters for all of us. I'm now preparing to cover my ninth General Election.
I've seen one parliamentary by-election on my patch. But this is the first local MP I've seen defect. Politics always has the ability to throw a curve-ball at you!
The opinions expressed in this column are the personal views of Paul Geater and do not necessarily reflect views held by this newspaper, its sister publications or its owner and publisher Newsquest Media Group Ltd.
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