One former party adviser said of the observation that it had been “quite the year” for Labour: “White Star Line: 1912 was ‘quite a year’ for Titanic.”
That was the only oblique reference Mr Corbyn made to the election disaster, failing to mention it directly even as he told the nation: “We’re up for the fight.”
Instead, he said: “We have built a movement. We are the resistance to Boris Johnson. We will be campaigning every day. We will be on the frontline, both in parliament and on the streets.
“And, make no mistake, our movement is very strong. We are half a million people and growing. We are in every region and nation of our country.”
Anne McGuire, a former minister for disabled people, tweeted: “Listen to this and weep.
“Think what might have been and how we sacrificed those who most needed a Labour government to a delusional ideology that thought echo chamber rallies were a substitute for persuading ‘the many’ to vote Labour.”
Jim Fitzpatrick, a former farming minister who left the Commons this month, said: “Let’s have lots of demos where we can talk to each other, again!
“Consistent in their belief that parliament isn’t most important, the ‘resistance’ is what matters.”
And Michael Dugher, a former transport spokesman, who stood down in 2017, also taunted Mr Corbyn, saying: “Meet Lieutenant Hiroo Onoda of the Japanese Imperial Army.
“The year is 1974. Lieutenant Onoda has spent nearly three decades holding out in the jungle on an island in the Philippines, refusing to accept that the Japanese lost the Second World War back in 1945.”
Neil Coyle, who is still a London Labour MP, responded to the broadcast by saying: “Labour isn’t a rent-a-mob protest party, or a ‘resistance’, but a potential party of government when led well.
“Corbyn’s team/message sank us to pre-war levels of representation. More poverty, homelessness and higher food bank use will be the result.”
On 12 December, Labour was crushed to its lowest number of MPs since 1931, forcing Mr Corbyn to announce he will quit when a new leader is elected in March.
In his message, he said: “2020 and the years ahead will be tough, no one is saying otherwise. But we’re up for the fight, to protect what we hold dear. And to build to win and to transform.
“The fight continues. There is no other choice. So if you’re with us already, I can’t wait to meet the challenges ahead together.”