Expect plenty of incendiary rhetoric and anti-Israel firebreathing when Britain's trade unions gather in Liverpool next week.

In July, Britain's biggest trade union, Unite, set the tone with a series of inflammatory attacks on Israel, in which they labelled it "an apartheid state", condemned "the oppression faced by ordinary Palestinians at the hands of their colonial oppressors", and suggested of Operation Protective Edge: "This isn't about rockets from Gaza. It's about Israel fighting to maintain its control over Palestinian lives, and Palestinian land. It's about Israel feeling able to commit war crimes with complete impunity".

Prior to the escalation of the war between Israel and Hamas, the Trade Union Congress' governing body - the General Council - had been attempting to douse the flames. In its report to conference, published in late July, the Council provides an update on a motion passed two years ago mandating it to send a delegation to Gaza in conjunction with the Palestinian Solidarity Campaign. Clever tweaking by TUC leaders suggests the delegation - due to visit in November or December - would travel via Israel and meet the leadership of Histadrut, the Israeli version of the TUC. Attempting to side-step Hamas, the delegation will be escorted by the Palestine General Federation of Trade Unions (a body whose members have been the target of the Islamists).

Now, however, observers of the trade unions' debates on Israel believe the conflict may spark another fire-fight on the conference floor. They fear a possible emergency motion and a toughening of the TUC's 2009 decision in the wake of Operation Cast Lead to support a boycott of settlement goods. This is "a huge opportunity for the PSC to capitalise on misery", said one.

In 2009 a push for a full boycott was avoided by deft footwork by the former TUC general secretary, Brendan Barber. He managed to overrule the conference vote by persuading the Council to adopt a statement supporting a more limited bar on West Bank settlement goods.

Whether his successor, Frances O'Grady, has, or is willing to expend the same political capital this time is less clear. If an emergency motion is proposed, its fate will lay in the hands of Unison and Unite, two of the country's biggest unions.

But for Unite, wording may be all: with thousands of its members employed in the defence industry, its "statement of solidarity with the Palestinian people" in July conspicuously failed to support calls for an arms embargo against Israel. In a battle between Unite's desire to further its campaign to demonise Israel and the jobs of its members, jobs may just win.