Frank Field is in a great tradition of patriotic Labour MPs

There is still a Big Two: the Conservatives and Labour.

The Liberal Democrats did so well in 2010 that it seemed like a third party breakthrough for the first time since the SDP-Liberal Alliance in 1983, but sharing power with the Tories led to their vote collapse in 2015.

The only major breakthroughs politically have been the rise of Ukip through this century and also of the Scottish National Party. The former has seen its support collapse after Brexit.

And yet, for all the survival of the Big Two, huge forces are hitting politics across the western world, leading to the rise of radical left-wing movements and anti immigrant ones, and populists including the American president Donald Trump.

In Britain, the Conservatives are struggling to hold together.

In Labour, the rise of the hard left Jeremy Corbyn as leader has greatly increased internal strains within that party too.

Frank Field is in a fine tradition of a particular type of Labour Party politician: a tireless advocate for the poor but at the same time a defender of patriotic values. It is no exaggeration to say that if Brexit does come to pass, it will be in large part due to him and some similarly minded Labour MPs, including our own Kate Hoey, who have defied their leaders’ attempts to unseat Theresa May (which would put Brexit at risk).

Mr Field also was a supporter of welfare reform, feeling passionately that it entrapped some of the most disadvantaged people. For that too he was vilified.

Now he has broken with the party whip over the anti-semitism row that has engulfed Mr Corbyn.

As Boris Johnson said, criticising Israel fiercely does not add up to anti-semitism, but Labour has within it people whose hatred of Israel does cross that boundary.

Mr Field’s decision might hasten break-up of the party system. In the meantime, it is to be hoped that he stays in the House of Commons, as brave and original voice.