On 17 July 2018, a vote was held on a rebel amendment to a trade bill, which aimed to force the British government to join a customs union with the EU in the event of a no-deal Brexit. Field, Kate Hoey, John Mann, and Graham Stringer were the only Labour MPs to oppose the amendment, which was lost by 307 votes to 301. Field lost a confidence vote in his constituency, after siding with the government in these Brexit votes. On 30 August 2018, Field resigned the Labour whip because, he said, Labour was "increasingly seen as a racist party" and due to the "culture of intolerance, nastiness and intimidation" in parts of the party, including his own constituency. Some commentators suggested that he had "jumped before he was pushed."