The Ministry of Defence ran up a £40,000 bill on the speaking clock, despite a ban on staff calling it.
Employees were reportedly banned from dialling 123 to check the
They were given a list of websites they could use to get the time free,
but calls have continued - costing a total of £40,000 in less than three
An MoD spokesman blamed the "inadvertent spending" on a technical fault and said calls to the speaking clock had now stopped.
The final bill for 2012 was £18,804 and £15,162 in 2011, with more than £6,000 already spent this year.
Over the period since the ban was announced, the MoD has made more than 130,000 calls at 30p each.
An MoD spokesman said: "A ban was introduced to our newest telephone network, but due to a technical error with some IT servers there has been some inadvertent spending on the speaking clock which has now been
"Overall spend on this has decreased from more than £15,000 in 2011 to just £6,000 this year since the ban was
Labour's shadow defence minister Kevan Jones accused minsters of breaking their promise to tackle waste by allowing "thousands of taxpayer pounds" to be "squandered on costly calls".
"Personnel who have been made redundant or the public who have heard warnings from senior officers about the government's defence cuts will worry that waste is continuing.
"It is essential that a full ban is implemented. Ministers must give the country confidence that waste, rather than capabilities, is being cut." The speaking clock service was launched in 1936 and celebrated its 75th anniversary in 2011. It has never been a free service - in the early days, calls were one penny from home and two pence from a phone box.
It used to be called Tim as people would dial the first three letter of the word "time". It is now officially called Timeline.
In 2007, Sara Mendes da Costa from Brighton won a competition to become the fourth permanent voice for the speaking clock in a BT competition that raised £200,000 for BBC Children In Need.
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