Dozens of Labour MPs rebelled against party leader Jeremy Corbyn on Wednesday over the terms of Britain’s exit from the European Union.

Some 48 Labour MPs, including former Labour Cabinet ministers and ex-members of his own frontbench, backed a bid to keep Britain in the single market and customs union after Brexit.

The rebels included Daniel Zeichner, who quit as a shadow transport minister last summer, and former Labour frontbenchers Chuka Umunna, Ben Bradshaw and Chris Bryant.

They joined forces with Scottish National Party MPs, and Liberal Democrat MPs such as former leader Tim Farron. A single Tory MP, Ken Clarke, voted with the rebels.

The amendment to the EU Withdrawal Bill sought “confirmation of continued membership of the single market and customs union before ministers can implement any withdrawal agreement”. It was defeated by 322 votes to 99.

The 48 Labour MPs – about one in five of Labour MPs – voted against the party whip after being urged to abstain in advice from the leadership.

A leaked copy of Labour’s own advice to its MPs said that the amendment “pretends you can ‘guarantee’ the outcome of the negotiations and to remain a ‘member’ of the customs union and single market. It is not a serious amendment and it is not one the Labour frontbench will be supporting.”