“We are clear what we mean by that: the next Labour government will seek to build on this deal, not cheerlead for it,” she writes.
But Neil Coyle, the Labour MP for Bermondsey and Old Southwark, told The Independent he would abstain, leaving the prime minister to “savour” his damaging folly in the future.
“Johnson’s Tories have a government majority of 80. They don’t need any Labour votes to push their downgrade deal through Parliament,” he said.
Keir Starmer has sparked anger by ordering his MPs to back the Christmas Eve agreement – on the grounds that the only alternative is the disaster of a no-deal departure.
There has been criticism that the decision was announced prematurely, before the vast 1,255-page document was even released. Even now, a Bill is yet to be published.
In her article, Ms Reeves attacked the “historic mistake” of leaving the services sector – including accountancy, the arts, finance, media, law and architecture – high and dry.
“Our qualifications won’t be recognised in Europe making it harder for British businesses and individuals to win contracts abroad,” she has written.
But, she said, “only two, narrow paths” were left, adding: “Down one is Johnson’s limited and unimpressive deal with the EU.
“Down the other is the chaos of ending the transition period with no deal, which would mean substantial tariffs and barriers to trade.
“Neither one is ideal. Neither one will deliver for jobs, business or the economy. But a bad deal is better than no deal at all.
“A Labour government would inherit this deal in 2024. It may be the Tories’ ceiling of ambition, but for Labour it must be a foundation on which to build upon.”
But Mr Coyle added: “British people and businesses will be worse off under Johnson’s mess and it will take decades to fix the problems it leaves unresolved.”
And a second rebel, Exeter MP Ben Bradshaw, has criticised the apparent motivation to back the deal because it will “help us win back the so-called ‘Red Wall’ seats”.
“This is to fight the last battle, rather than the next one and where we will be at the next election. It buys into the false Tory and Lexiteer [left-wing Brexit supporters] narrative of why we lost so badly a year ago,” he wrote on his website.
At least a dozen Labour MPs are expected to abstain – with Clive Lewis among a smaller number considering a vote against – but Labour’s backing ensures the agreement will pass, in time for the transition period ending on New Year’s Eve.