Britain’s transport minister Jo Johnson on Friday resigned from Prime Minister Theresa May’s government in opposition to a looming Brexit deal and called for a second referendum on leaving the EU.

“It has become increasingly clear to me that the withdrawal agreement, which is being finalised… even as I write, will be a terrible mistake,” he wrote in a stinging resignation statement.

Johnson — who had backed staying in the EU in the 2016 referendum — is the younger brother of Boris Johnson, who spearheaded the pro-Brexit campaign and quit as foreign secretary in July over May’s Brexit blueprint. (AFP)

• Conservative party MP Jo Johnson leaves 10 Downing street in central London after the first cabinet meeting of the new year following a reshuffle on January 9, 2018. Daniel LEAL-OLIVAS / AFP