The Ministry of Defence has spent thousands of pounds on calling the speaking clock after failing to implement a ban on the number.
Since 2011 the Government department has spent more than £40,000 dialing the service, partly due to a "technical error with an environmental monitoring system" that resulted in "inadvertent" calls.
Last year it was reported that the MoD had brought in a ban on ringing 123 and staff had been informed of websites they could use to check the time instead.
But even with the ban, the final bill for 2012 was £18,804 and more than £6,000 has already been spent this year.
Added to the £15,162 the department spent in 2011, staff at the MoD made more than 130,000 calls at 30p each during the last two-and-a-half years.
That figure includes calls made by military personnel, of which there around 160,000, as well as civil service employees, of which there are around 80,000.