sharon graham
Unite general secretary Sharon Graham also urged to PM to ditch the "cruel" policy of taking winter fuel payments off millions of pensioners.
Sharon Graham says the former leader would win his seat of Islington North if he chose to stand.
Sharon Graham accused the government of a “real abdication of responsibility” over its refusal to budge on pay.
"In 25 years of negotiations, I have never seen such an abdication of leadership as I have with this prime minister."
A department of health source told HuffPost UK: "The government’s position on pay is unchanged - the country cannot afford to meet the unions’ inflation-busting demands."
The huge union is facing a £70 million loss on the controversial project.
Sharon Graham accused David Lammy of launching a "direct attack" on British Airways workers.
The union has been overtaken by Unison as the biggest in the country.
The row emerged the day after it was revealed the union is facing a £70m loss on a controversial hotel project.
The union spent nearly £100 million building the Birmingham venue, which is now the subject of a QC-led inquiry.