Conservative MP Larry Brock is resigning as the member of Parliament for Brantford-Brant South-Six Nations, according to three sources who spoke to The Globe and Mail (The Globe and Mail).

A source told the newspaper that Brock planned to inform his riding association on Thursday night of his decision to leave at the end of the summer. The Globe and Mail did not name its sources because they were not authorized to publicly discuss Brock's decision. Brock did not return calls from the newspaper.

Brock was first elected in 2021 and is a former Crown prosecutor — a government lawyer who handles criminal cases on behalf of the state. He won his riding in the last election with 52 per cent of the vote. The riding of Brantford-Brant South-Six Nations was listed as "leaning" Conservative on 338Canada.ca.

He served as the Conservative justice critic until Pierre Poilievre shuffled him out of that position in June. A justice critic is the opposition MP responsible for questioning and challenging the government on justice policy. Brock said at the time he was stepping aside for personal reasons. On June 30, 2026, Brock published a statement on his official Facebook account titled "Statement from Larry Brock on Stepping Back from Shadow Cabinet," dated for immediate release (Facebook).

Brock will be the seventh MP to leave Poilievre's Conservative caucus since the 2025 election. The departures span a range of circumstances, from floor-crossings — when an MP leaves one party to join another — to Senate appointments to retirements.

Four MPs have crossed the floor from the Conservative caucus to the Liberals since the 2025 election. Saskatchewan Conservative MP Cathay Wagantall, the fifth departure, had said last year she would not run again but would serve out her term, then announced she would step down on Aug. 31. Quebec Conservative MP Richard Martel, the sixth departure, was appointed to the Senate by Prime Minister Mark Carney. A by-election for Martel's former riding of Chicoutimi-Le Fjord is scheduled for the end of August.

The Chicoutimi-Le Fjord contest carries its own political weight. Carney said the Liberals' choice of former dairy producer Daniel Gobeil to run in the riding shows the government is loyal to supply management — the system that controls how much farmers produce and sets minimum prices for products like milk, eggs and poultry. The United States has cited Canada's supply management as a key irritant in trade negotiations. Poilievre visited the Chicoutimi-Le Fjord riding earlier in the week of the Brock report.

The broader context here is a Conservative caucus that has been steadily thinning since the 2025 election, through a combination of floor-crossings, retirements, and now a resignation. Seven departures from a single caucus in roughly eighteen months is a rate that will draw attention from party organizers and House leadership alike, particularly when four of those members went directly to the governing Liberals. Each departure narrows the margin available to the Official Opposition on confidence votes — parliamentary votes that, if lost, can bring down a government — and committee composition, and each triggers either a by-election or a vacancy that shifts the riding-level map.

Brock's case is distinct from the floor-crossings and the Senate appointment. His removal from the justice critic portfolio in June, followed by a public statement framed around personal reasons, and now a planned resignation at summer's end, traces a compressed arc from shadow cabinet to exit. For a party that has placed criminal justice and bail reform at the centre of its messaging, losing the MP who held the justice brief is a portfolio-specific setback on top of the numerical one.

The by-election timeline for Brantford-Brant South-Six Nations has not yet been set. Under the Parliament of Canada Act, a writ for a vacancy must be issued no later than 180 days following the date the Speaker is notified. That clock has not started, given Brock has not yet formally resigned his seat, only signalled his intention to do so at the end of the summer.