Refusing to contest an opponent isn't the same as defeating them. The major parties' decision to sit out the 2026 Clacton by-election illustrates why I think a boycott can be a poor response to a political stunt.
Farage still had opponents. The council's result records a contested election, and it would be wrong to describe the seat as literally uncontested. But the absence of the main parties changed the contest substantially.
The case for staying away
There is a reasonable argument that parties shouldn't let an opponent decide where they must spend their time and money. A by-election deliberately triggered by a sitting MP can be an attempt to turn difficult questions into a fresh campaign. Contesting it may help give that strategy attention and legitimacy.
Parties also have limited resources. Standing a candidate isn't a promise to spend without limit in every seat, and choosing a contest carefully isn't automatically contempt for the electorate.
My objection is to assuming that withdrawal answers the political argument. The opponent can still win, claim endorsement and present the absence of major rivals as evidence that they had nothing to offer.
Give voters an alternative
If a party believes a constituency is being used for a stunt, it can say so while offering people someone else to vote for. It can argue about the MP's record and the local interests the campaign has displaced.
That won't guarantee victory. It at least asks voters to choose between competing accounts, rather than hoping they will treat the missing candidates as the more persuasive case.
There are circumstances in which a boycott may be justified. I don't think distaste for an opponent is enough on its own. If people are willing to support a political movement, those who want to defeat it need an answer they can put in front of those people. Declining to turn up leaves that job undone.