TUBE workers could be balloted for industrial action if cleaners boycotting fingerprint-based clocking-on machines remain locked out.

Transport union RMT said branch resolutions had gone forward calling for non-cleaning staff to be balloted over the very presence of the biometric technology in Tube stations.

Cleaners working for contractor ISS on the Piccadilly, Northern and Victoria lines objected to the new clocking-on system, arguing it is an affront to civil liberties and could be used to intimidate migrant workers.

Bosses locked out 14 workers for refusing to sign-in with the new system despite an agreement with the union that no-one would be forced to switch over to the Orwellian fingerprinting.

Despite being kept out for 10 days the workers have vowed to keep fighting.

RMT rep Richard Crane said: “ISS just don’t give a monkey’s. They’re still not talking or coming to the negotiating table.

“We’re not heroes — we’re just ordinary people who have had enough of bullying and intimidation.”

He said he and his colleagues had found considerable public sympathy, but that a protest at ISS’s Canary Wharf offices had ruffled security guards.

“They said that they’ve had nothing but protests since ISS moved into the offices.”

The campaign has attracted support from left Labour MPs Jeremy Corbyn and John McDonnell — who are urging Commons colleagues to write to ISS and Tory London mayor Boris Johnson. RMT parliamentary group chairman Mr McDonnell is also seeking to raise the matter in a Commons debate.

But RMT assistant general secretary Steve Hedley said the union was also preparing for industrial escalation.

“London Underground members are now suggesting a ballot on the very fact that these machines are in the stations,” he said.

“This wouldn’t be secondary action. It’s perfectly legitimate for our members to object to have fingerprinting technology in their workplaces.”

The RMT said it already had agreement with management to avoid biometric clocking-on on the remainder of the Underground’s lines.