British public-sector employees are upset by a plan to make them work an additional six years before collecting their pensions, UPI quoted union leaders as saying. Union officials in a Daily Telegraph report Friday called the plan "gunboat diplomacy" and warned it could kill talks to avert strikes. The age at which most state employees can draw pensions will rise from 60 to 66 by 2020, bringing them in line with Britain's private sector. Danny Alexander, the chief secretary to the treasury, said public-sector employees would also be required to pay additional money to the retirement system. Alexander warned Britain's millions of public-sector employees it would be a "colossal mistake" to turn their back on the government's plans. Gail Cartmail, Unite union assistant general secretary, said Alexander's comments are "tantamount to bombing the talks" now under way to deal with a planned strike of 750,000 teachers and civil servant workers. "As a result, millions of public-sector workers, many of them women, such as classroom assistants, health visitors and nursery nurses, are in the firing line and face complete uncertainty about their future pension," Cartmail said.