The Government’s defence of the fisheries section of the transition agreement is that Britain’s share of catch can’t be reduced during the transition period, that this guarantee is underpinned by a good faith obligation on the EU, and that by December 2020 we will be negotiating fishing opportunities as a third country and independent coastal state.

None of this cut much ice with Conservative MPs yesterday in the Commons, as they queued up to protest against the fisheries deal – their vehicle being an urgent question answered by Michael Gove.  The Environment Secretary and committed Brexiteer did his best to soothe anxious and angry Tory backbenchers, but his heart clearly wasn’t altogether in his mission and, presumably in consequence, he seems to have had difficulty in getting his head round the case that he was tasked with making.  So it was that he told Jacob Rees-Mogg, who pointedly asked what the UK would get in return, that the “big prize” won was the implementation period itself…before agreeing with Desmond Swayne that “it is just as well that the implementation period is shorter than was sought, isn’t it?”

Behind the scenes, MP friends of Gove suggest that either David Davis or Theresa May or both simply weren’t tough enough on the EU during the talks.  Davis’s supporters say that the Prime Minister ultimately controls the negotiation and must take responsibility.  Either way, Downing Street, the Treasury and the Whips Office have clearly underestimated the talismanic power that Britain’s fishermen exert over the imagination of many Brexiteers.

Some of them have long memories, citing Edward Heath’s fishing agreement, when Britain entered the Common Market, under which our jurisdiction extended only to twelve miles beyond our coasts, as an emblematic betrayal of British interests.  (In his memoirs, Heath claimed that “fishing has become controversial only because of four developments since 1974: the extension of national fishing limits to 200 miles, the accession of Spain to the European Community, the necessity of conserving fish stocks and the sale of fishing licences by British fishermen to Spanish interests”.)  Fishing jangles nerves, as it did when Bob Geldof and company flicked V-signs on the Thames at fishermen during the referendum campaign – a gesture that duly backfired.

Furthermore, there is the Scottish angle.  The repatriation of fishing has played a significant part in the Ruth Davidson-led revival of the Tory cause in Scotland.  The newly-elected Scottish Conservative MPs are up in arms.  Douglas Ross has said that “it would be easier to get someone to drink a pint of cold sick than try to sell this as a success.”  John Lamont’s view is that “no deal for fishermen and they will have to think again on the terms of our departure.”

Philip Hammond is doubtless correct to to have pointed out within Government that the industry is a relatively small one, and that the contribution of financial services to the economy is larger.  And it follows that the Treasury believes that access to British waters post-Brexit should be bargained off for access to EU consumers – or, more broadly, for minimum friction in trade for manufactured goods.  But what may be a small industry in economic terms can be a big one in political terms.  The lesson of this week is that such a trade-off, explored recently by Mark Wallace on this site, will be very difficult to agree indeed – at least if the support of a significant tranche of Tory MPs is to be won.

Meanwhile, ponder a dog that hasn’t barked – or has only growled, at any rate.  The Prime Minister has met with Conservative MPs to soothe them over fisheries, or try to.  Gove has been summoned to the Commons for an urgent question.  But given that immigration was the second biggest driver for the Leave vote, where is the backlash over free movement continuing until the end of transition?  Why aren’t Tory MPs similarly up in arms?

There seem to be five main reasons.  First, the Government made gains over the rights of British citizens within the EU post-transition. Second, the cause of lower immigration has no public champion within Cabinet, though Davis and Gavin Williamson make the case behind closed doors.  Third, Number Ten quietly conceded on free movement a few weeks ago.  Gove, together with Ruth Davidson and Scottish Tory MPs, kept up their stand over the early repatriation of fisheries, and there is usually more of a row about folding late than early.  Fourth, backbench pressure over fisheries is local and visible, extending from those attention-grabbing Scottish constituencies to ones elsewhere in the country.  Finally, the recent fall in net EU migration may be making an impact on public opinion.

Ministers may count on this calm lasting.  That would be unwise.  But just as they have the opportunity to get a durable settlement for fishing in place for post-transition, so they have a chance, too, to begin planning a sensible post-transition immigration policy based on a cap, work permits and greater access for countries with which we strike future trade deals.