The landlord of a Norfolk pub has warned he has lost half his takings over three days after he fell victim to what he believes is phone slamming.

Phone slamming is where phone customers are switched from one company to another without their knowledge or consent. It can affect broadband and telephone lines and is classed as "an extreme form of mis-selling" by Ofcom, the regulator for communications services.

Paul Sandford, the landlord of The Railway Tavern in Dereham, first realised something was wrong was when his internet went down on Wednesday, September 1.

The publican phoned BT to report the fault but was told his line "was no longer a valid line".

Mr Sandford said: "BT told me my line had been put for transfer to another company. We still don't know who the company is. Someone from BT said I had been a victim of phone slamming which I hadn't heard of."

Since Mr Sandford fell victim to the scam, he has been without a telephone number or broadband, losses which he says have had "a terrible impact on the business" because no one has been able to place takeaway orders.

"No one knows how it happened and why it has happened - if it can happen once it can happen again," he said.

"It could have been done intentionally but I would like to think it hasn't been, either way, it's quite concerning. It's a real blow, it's literally halved our takings over the last three days at the time when we are trying to get back on our feet."

A BT spokesperson said: “We’re sorry about Mr Sandford’s experience and any disruption to his service. We have investigated the issue and have requested to reinstate Mr Sanford’s line which will be up and running as soon as possible.

"In addition, we will offer a gesture of goodwill for the inconvenience caused. We would advise any customer who believes that they may have been slammed by another provider to report the incident to Ofcom who will investigate and take action against any company found to be mis-selling.”

While Mr Sandford is attempting to reinstate his phone line, something he has been told could take until September 13, he has set up a temporary number (01362 700332) which customers can use to place takeaway orders.

What is phone slamming and how common is it?

Phone slamming is where customers are switched from one company to another without their knowledge or consent. Ofcom classes it as a "completely unacceptable and an extreme form of mis-selling".

The regulator receives around 80 complaints a month about slamming.

When a company such as BT receives a request from another service provider informing it that they wish to take over a phone line BT sends writes to the customer to let them know.

Customers are then given 10 working days to inform the company if this request isn’t accurate.

To avoid being slammed Ofcom advises people to be wary of giving out personal information over the phone.

Anyone who receives notice of switching who does not want to switch should tell the provider they did not agree to the transfer. If this is done within 10 days, they will be able to put a stop to the transfer.