There are occasions when the MSF transmission is off. This can be checked by telephoning 020 8943 6493. It is possible however that your clock uses the DCF-77 signal from Mainflingen in Germany. If your clock has worked well in the past but cannot now set itself you should check whether the batteries need changing, or whether there has been a change in its environment. Perhaps you have altered the position of the clock, or there may be a new local source of interference, such as a television or personal computer in use nearby, or a wireless burglar alarm. Try taking the clock well away from buildings and metalwork to see if it still works there. If a new clock fails to function correctly even with fresh batteries and when away from sources of interference and screening you are advised to contact the supplier.