Smart meter displays have randomly switched to Welsh baffling English homeowners in the latest glitch to plague users of the devices.

Several customers of Bulb contacted the advice site Moneysavingexpert.com to say that their in-home display had switched from saying “today’s usage” to “Defnydd heddiw”. In order to fix the problem the non-Welsh speakers were told they had to navigate a five-step menu in Welsh.

But when the Daily Telegraph showed the menu options to a native Welsh speaker he described them as “gibberish”.

For example, at one stage users are given the option “Clirio Gosodiadau Wedi anfon yr” which the Welsh speaker said directly translates as “clear the installations has been sent”.

Bulb, which has 1.3 million customers, said the problem only affected one in 200 of its smart meters and was the result of a software issue with the in-home displays.