Lambeth College staff who went on a five-week strike earlier this year will vote on whether to take further industrial action after rejecting “improved” offers over contract changes.

University and College Union (UCU) members walked out indefinitely on June 3 in a dispute over new staff contracts introduced on April 1, which the UCU said would leave staff with longer working hours, less sick pay and less annual leave, before returning to work on July 9.

The UCU shelved a ballot for further strike action mid-voting three weeks ago to allow members to consider whether to accept “improved” offers from college bosses.

But these were rejected by 92 per cent of branch members who voted — although it is understood less than 55 per cent of UCU members who work at the college took part in the ballot.

A UCU spokesperson said a ballot asking members whether they supported further industrial action “up to and including indefinite strike action” would be launched today (November 3) and close on November 17.

He said: “The latest proposals tabled by the college were roundly rejected by an overwhelming majority of UCU members.

“Our members are dedicated to their learners and would much prefer to be teaching than thinking about further industrial action but [college principal] Mark Silverman needs to address what are clearly widely held objections within the college to the introduction of inferior contracts that creates a two tier workforce.”

The college offered a guarantee that staff taken on before April 1 would have stayed on the original contract until at least September 2017.

Alternatively, existing staff could have accepted a £1,500 “cash incentive” to transfer to the new contract by September 2016.

Both options were dependent on staff agreeing to work an extra hour per week from September — increasing their overall annual working hours from 828 to 864.

Mr Silverman said: “It’s extremely disappointing that UCU has rejected what we offered.

“We should remember that this dispute is about a new contract for new staff. The new contract does not need to apply to staff employed by the college before April 1.

“It was UCU that said there needed to be a single contract [for old and new staff]. We made what I think was a very reasonable offer to move towards that, which was rejected.

“We are working on a plan to deal with any possible strike action, but haven’t got to the stage yet of knowing how many staff will be on strike or when it will take place, so it is too early to talk about specific measures.”

The college was slapped with an Ofsted grade four rating in 2012 but worked its way up to a grade three last year.