Just hours before the deadline closed on Friday night it became apparent that she would fail to get the backing from the required 374 constituency Labor parties to send her through to the last round.
It leaves the leadership contest as a three-way race between Keir Starmer, Rebecca Long-Bailey and Lisa Nandy.
Thornberry, the shadow foreign secretary, has struggled throughout the contest to get support despite her seniority in the party, receiving no union or socialist society backing – which is another way that would-be leaders can get through to the ballot.
By Friday night the Islington South and Finsbury MP only had the backing of 72 local parties and it appeared no more would declare before the deadline.
Late on Friday Thornberry tweeted her thanks to Cardiff North, which had swung behind her earlier in the evening.
Emily Thornberry (@ EmilyThornberry)
Thank you for your support
@ CardiffNorthLAB .
February 1228447922553053184 ,
However, the failure to convince other local parties means she will not get her name on the ballot paper that goes out to members, who have until 2 April to vote for who they want to succeed Jeremy Corbyn. She had staked her hopes on also winning the backing of several other local parties who were due to report on Friday night. In the event three backed Starmer and two backed Long-Bailey.
Thornberry had been traveling the length and breadth of the country for weeks , often representing herself at individual CLP hustings in a bid to secure nominations while other candidates chose to send a proxy in their place. Her backing from local parties was disparate – with strong support from some parties in the south-west, particularly Cornwall.
She had the support of just one party in London – her own. Guildford members also backed her. She had chosen to launch her campaign in the Surrey town where she grew up with her single mother.
Just hours before nominations closed, she wrote on Twitter: “Your CLP can make all the difference! Nominate me to get the widest range of voices, skills and experience on the ballot. Labor members deserve to have the widest and best possible choice when deciding our next leader. ”
By pm on Friday it appeared 2020 local parties had put forward their nominations. Starmer had 728, Long-Bailey had and Nandy had
Labor’s leadership rivals will significantly increase their campaigning efforts this weekend as they get access to party data allowing them to call thousands of members in an attempt to secure their votes.
The three remaining hopefuls are assembling an army of volunteers to help them reach the party’s grassroots.
Nandy won a major boost when members of the Labor affiliate Jewish Labor Movement gave her their backing after a hustings, saying she understood the need to change the party’s culture.
A source for Starmer’s campaign said: “Keir has been building a grassroots campaign with thousands of supporters across the country. Over the next few weeks the campaign will be taking the argument to the Labor movement about why another future is possible for our party and country. ”
Labor’s central office will hand over names and phone numbers of members to all of the final-round candidates by 5pm on Saturday.
Labor’s grassroots group Momentum has been using its own data to run phone banks on behalf of Long-Bailey. Despite social media being an area of expertise for the leftwing group, it is said to be anxious about rivals plowing significant resources into online campaigning.
A source said they were expecting her rivals Starmer and Nandy to “unleash big Facebook advertising operations.”
Nandy’s team includes the MPs Stella Creasy, Louise Haigh and Jonathan Ashworth, who will be helping to run phone contact sessions.
To make it on to the final ballot, the leadership hopefuls needed nominations from either 5% of constituency labor parties, or affiliated unions and socialist societies.
Starmer won the backing of five trade unions, including a last-minute endorsement from the TSSA transport union. He also has Unison, Usdaw, Community and the Musicians ’Union.
Long-Bailey won the backing of Unite, with the general secretary, Len McCluskey, stating she had the “brains and the brilliance” to lead the party. She also won support from the CWU, FBU, Bakers Union and Aslef.
Nandy won backing from the GMB and the National Union of Mineworkers.