In unusually strong language, the Labour leader said the Brexit camp was telling “outright lies” when it claimed that more money would be available for the NHS after leaving the EU.
Corbyn has been accused of sounding lacklustre about the EU during the campaign, and recently graded his enthusiasm about staying in at 7.5 out of 10.
But appearing with the entire shadow cabinet, members of Labour’s ruling body and trade union chiefs at an event in central London on Tuesday, Corbyn said: “It is the Labour position, the trade union position to vote to remain. We urge our supporters to think carefully and vote to remain.”
He said Brexit campaigners such as Johnson, Michael Gove and Iain Duncan Smith were showing “faux concern” about the NHS.
“A vote to leave is a vote to put the NHS in jeopardy and in the hands of those who want to break it up,” he said. “Nigel Farage and Boris Johnson are wolves in sheep’s clothing, using concern about the NHS to mask their real agenda.”
Addressing concerns of those on the left about the TTIP trade deal between the EU and US, Corbyn said it would be better to fight it from within the bloc to protect public services across Europe.
The event was introduced by several union leaders, a midwife, a medical researcher and an ambulance worker, who emphasised the desire of some leading Brexit campaigners to dismantle the NHS.
Frances O’Grady, general secretary of the TUC, derided Johnson, Duncan Smith and Gove as “fibbers, fakes and phoneys” and said they were on record as having suggested alternatives to the current system.
“When did their leading lights every give a toss about our NHS,” she said. “The hard right Tories and Ukip … They love the NHS in a way that Dracula loves a blood bank.”
Dave Prentis, the boss of Unison, the biggest union of health workers, said: “I don’t think I’ve ever seen a campaign as deceitful as the one being waged by the leave campaign.
“These are the people we have been fighting tooth and nail. Michael Gove writes in books that [the NHS] is not fit for the 21st century … I’m sick of the British people being lied to.”
Prentis urged people to “see through the lies”, adding: “Do not, do not, put our NHS at risk when you vote on 23 June.”
This article was written by Rowena Mason Political correspondent, for theguardian.com on Tuesday 14th June 2016 13.48 Europe/Londonguardian.co.uk © Guardian News and Media Limited 2010