Opposition councillors have launched a last-ditch bid to scupper plans to outsource the borough's libraries by pledging to tear up any contract if they win next year's local elections.

Croydon Council's Labour group promised it would end any deal with outside partners and fired a warning shot to bidders by claiming it would take legal action if necessary.

The contract to run Croydon's 13 libraries went back out to tender this month after the council failed to agree terms with its preferred bidder.

At an emergency meeting on Monday the council's opposition group tabled a motion calling for the outsourcing process to be scrapped and replaced with a co-operative model that would see volunteers team up with in-house council staff.

The motion was defeated 35 to 30, but Labour's leader, Councillor Tony Newman, said he hoped it would help to dissuade potential outsourcing partners.

He said: "We are making it very clear that we are going to put the will of the people ahead of the contract.

"We are publically warning now anybody bidding for this contract, for which there is absolutely no mandate at all, that if Labour win the 2014 local elections we will abide by will of the people. Residents have shown in success consultation that they do not want libraries to be privatised. 

He added: "We are putting a shot across the bows of any bidder that we will immediately look to tear the contract up.

"Clearly Plan A would be to negotiate the end of the contract rapidly with anyone who has taken it on, but then if need be would take stronger action."

Councillor Tim Pollard, cabinet member for children, families and learning, insisted there was no evidence Labour's proposed outsourcing model would work.

He said: "It would be uncosted, untested, confusing, inefficient and unsustainable even if it was implemented.

"There is no example of the co-operative model having made the transition from idea to reality."

Campaigner Elizabeth Ash, of Save Croydon Libraries, argued neither outsourcing nor co-operatives were satisfactory and called for improvements to the current library services instead.

She said: "The council are not doing what residents want,  but residents don't want to run libraries either. 

"I just wish someone was saying they could come back to the table and find a way to keep it in in-house."

The deadline for bids to run the libraries is in April and the council expects to announce its preferred bidder in June.