The ban lasts until the providers – Daligas, Enstroga, Entice Energy Supply, Euston Energy (trading as Northumbria Energy), and Symbio Energy – become compliant.

The issue relates to the suppliers failing to sign up to a communications system bridging the technology gap between the older SMETS1 smart meter and the newer, next generation SMETS2 smart meters.

By not being part of the scheme, it means smart meters lose their functionality when customers switch from compliant firms to the non-compliant ones.

As such, customers will have to provide manual meter readings.

Energy regulator, Ofgem said this causes “consumer detriment and could undermine consumer confidence in the smart meter programme and the switching process”.

Earlier this year, Ofgem warned nine energy suppliers they could have their licences stripped if they failed to become Data Communications Company (DCC) users.

Three of the suppliers (Ampower, Green Supplier Limited, UK National Gas Ltd) have since become compliant.

Better Energy Limited has not been issued with a final order as it no longer has any domestic customers. Its licence will be revoked later this month.

But the five suppliers named above have still failed to become DCC users and will now be banned from taking on any new customers until they become compliant.

Ofgem said it will consider further enforcement action, which could result in their licences being revoked.

‘Hefty punishment’

Will Owen, energy expert at Uswitch.com, said: “These five energy companies might not be household names, accounting for fewer than 100,000 households between them. But the smart meter network won’t work properly until every supplier is using the same communications infrastructure.

“All suppliers were meant to be enrolled in the DCC smart meter infrastructure by November 2017.

“Banning a supplier from taking on more customers is a hefty punishment, and could seriously damage their growth plans.

“These companies could face further punishments, and potentially lose their licences if they don’t resolve this situation soon.”