Seventy thousand construction workers employed by councils are being balloted for strikes in a row over pensions.

Construction unions UCATT, T&G, Amicus and GMB have agreed to ballot workers for strikes after failing to resolve a long-running dispute with government over plans to make temporary cuts to workers' entitlements. The unions have called on deputy prime minister John Prescott to step in and resolve the situation before the industrial action.

Alan Ritchie, UCATT general secretary, said: "It is unfortunate that the dispute has reached this stage, but we believe that the entitlements of existing members of government pensions schemes should be honoured. We are still trying to find a political solution, and are in the process of writing to John Prescott as the regulator of the scheme asking him to review the situation."

The dispute centres on the government's attempt to remove the so-called 'rule of 85', which states that workers can retire without cuts in benefits if the sum of their age and length of service totals 85 years. The government claims EU rules on age discrimination make this clause illegal, a decision contested by unions.