The Conservatives won the seat at the last general election as the Red Wall backed Boris Johnson.
GMB and Unite unions announce action in response to a dispute over pay.
The Conservatives risk losing to Labour in the north and the Lib Dems in the south.
"This is the Truman Show or some sh*t," one critic tweeted.
“When we stand in line to vote, we are more likely to be hit by lightning three times than to be queuing behind someone who is committing voter fraud."
In a heated BBC Newsnight exchange, the RMT Union leader also said he would be happy to negotiate with the Tory government.
Opinion polls suggest Labour is on course to reclaim the Red Wall seat, but people are far from convinced by the party leader.
It wasn't exactly a glowing review of the prime minister.
Conservative Nadeem Ahmed says Imran Ahmad Khan was "one bad apple".
“We need to talk to a new generation in the same way Cameron, Osborne, and yes for eight great years, Boris did in London.”