Bradford Council faces a summer of strikes after the breakdown of more union talks - this time surrounding a £100 million computing contract.

Discussions about transferring management of the authority's computer network to an independent company have ended in deadlock, with union leaders set to advise staff they should walk out.

Members will be asked to hold a strike ballot. Four unions are already staging an unrelated one-day walk-out on Wednesday and say more could follow.

Public services union Unison says there are only around 105 Council computing staff but their work covers almost every aspect of the business, from council tax collection and processing to e-mail and telephone services.

Talks about the Bradford-i project stumbled over staff's fears their jobs would be gradually transferred to ITNet - the company bidding for the contract.

Patrick Kerry, Unison's lead negotiator, said: "We feel they have reneged on the agreement we thought we had last month. We have informed management we will meet staff and consider taking an industrial action ballot. A strike by computing staff would bring the Council to a standstill. It would cripple the authority."

Councillor Kris Hopkins, the Council's executive portfolio holder for corporate matters, said the development was "extremely disappointing", adding: "We have not accepted or rejected anything at this time. If anyone is walking away, it is the unions, not us, because we have not finalised the package we are looking for. If we had, there may be some logic in this."

A Council spokesman said staff had been given a choice whether to transfer to the computer company or stay as Council employees. "In either case," he said, "conditions of service will be protected, including pay and pensions.

"The Council will continue to work with the unions to avoid industrial action. If staff ultimately take strike action we will do our best to minimise disruption."

Unison says the Council may also face a summer strike over its Asset Management Project (AMP). Mr Kerry said the plan to transfer public buildings to a private partner raises similar issues to Bradford-i.

He said: "Bradford is in crisis with its employment models. We will not accept any transfer into the private sector; we want to protect members. Bradford could have a summer of discontent."