There are two competing narratives about MP Tristram Hunt’s resignation from his seat in Stoke-on-Trent, to take over the Victoria and Albert Museum. The first, distilled in the portentous tweeting of David Miliband, is that he is a good man, a brave man driven from the party he loves by the rabid left in a move that is “happy for him, sad for [the] party”.

The second is that he was a vacuous, entitled, money-grabbing New Labour poster boy who reveals the full extent of his self-interest in his willingness to ditch the party just when it can least afford to lose a seat.

Both arguments are pretty well meritless. Hunt was a half-hearted MP of shallow beliefs, making limp statements about low wages one minute, blogging for the Huffington Post about right-to-buy handing cheap homes to immigrants the next. He was, by the most meaningful measure – the proportion of constituents who voted for him – the least popular MP in Britain.

Even to a leader with whom he was ideologically aligned (whatever Hunt’s ideas are), he would have been a liability; to Jeremy Corbyn, he was blank anathema. So claims that he was damaging the party don’t make sense either: he was not, and never pretended to be, an ally – and they neither had, nor affected, any illusions that he was. If they had the confidence they claim – that a more radical, less antiseptic candidate could reignite the passion for the party that once earned the area the euphemistic “heartlands” tag – they should be pleased to see the back of him.

Had Hunt resigned on principle, it would have been no more remarkable or deplorable than ill-health or personal disgrace, the other two classic reasons for leaving the House of Commons between elections. There was a brief period in the 1980s when two MPs left to go and make daytime TV, which you can file under ill-health or disgrace, as you see fit.

Five years ago Louise Mensch left for “family reasons”, and could be seen as a “career MP” if by “career” you mean “relentless quest for attention”. David Cameron stood down as leader because he didn’t see why he should have to do “all the hard shit” over Brexit, a callow-sounding sentiment at the time, from the man who had caused all the hard shit, but one with which we cannot now do anything but sympathise.

MPs leave to join other parties or to seek other elected office, usually to become mayors. But it is more or less unheard of for an MP to leave because they’ve been offered a better job. Hunt isn’t even the first – Jamie Reed resigned his Copeland seat just before Christmas to take a job at Sellafield. According to the PoliticsHome website, one unnamed MP put it baldly: “There are scores of us who would quit if we had another job to go to because we know that the party has no chance at the next election.”

Again, to see that hopelessness as a reality and resign on principle would be one thing – arguably a good thing, since the personal, political and national cost entailed by a party limping into an election represented by people who neither expect nor want it to win will be some whole new brand of unaffordable. But to wait until you have a better job offer is odd – and when I say “odd”, I mean as close as we get, without having a constitution, to being unconstitutional. This effectively takes membership of parliament as just another job, dispensable upon receipt of a better offer, a contract no deeper than its terms and conditions, a waypoint on a career to which it will hopefully prove beneficial.

We use the term “career politician” as a pejorative, but usually to indicate someone a bit too slickly dressed, who puts their own advancement before their promises. We rarely mean it so literally.

Technically, you’re not allowed to resign from parliament, and a legal fiction had to be invented to enable it – departing MPs are appointed to an office of profit under the crown (Stewardship of the Chiltern Hundreds or the Manor of Northstead), which disqualifies their membership of parliament, effectively dissolving the bond of duty to constituents, with a superseding, made-up duty to the Queen. Of course it’s archaic, but it also contains and describes a fundamental truth about representative democracy: that MPs are the servants of the voters; they begged that service, and won it. Only the voters, not party grandees, can release them from it.

It’s understood that voters are reasonable people, and will release anyone who feels they can no longer perform the duty. But any MP who thinks the bond itself is archaic should consider its alternative. Try running a campaign with the top line, “I will fight for my constituents while there’s breath in my body, or until I get some number with better pay and less hassle, whichever is the sooner.” Not even the clubbable pseudo-authenticity of Boris Johnson or Nigel Farage could make this fly.

There is an argument that the Palace of Westminster could use a little more professionalism: that if we were to reframe our expectations, see this as a job rather than an act of public service, it would entail some proper training. Education and environment secretaries might be required to listen to the experts in the field, rather than dismiss them as “blobs” and “green blobs”. A well-informed health secretary might know something about social policy. Housing ministers might have to use the word “affordable” correctly. The argument upon which Conservative rhetoric hangs – that all problems in the public sector are caused by its recalcitrant employees – would collapse under the shame of knowing its falsehood.

With humility on both sides, we could incorporate careerist structures without relinquishing the expectation of civic duty. Instead, we have the worst of both worlds: a carnival of amateurishness in which the only discernible professionalism is in the exit strategy.