You could be prosecuted if your broadband interferes with radio signals

Thousands of homeowners could face prosecution if their broadband persistently interferes with radio signals, under Ofcom proposals published after lobbying by intelligence agency GCHQ.

The Government agency has become increasingly concerned in recent years about "power line" networking equipment. This allows people to use the mains wiring in their homes to transmit data, as an alternative to a Wi-Fi network, and has been distributed to BT and TalkTalk customers to connect their television set-top boxes to broadband.

Ofcom, the communications watchdog, published a consultation on Monday on new regulations that would allow its officials to issue enforcement notices to shut down such networks when the electromagnetic radiation they can emit interferes with radio signals. Those who fail to comply will face criminal prosecution.

An Ofcom spokesperson said: “Ofcom’s proposals are designed to update existing regulations to take account of developments in technology. They are not in response to requests from any organisation.”

As well as interference causing security issues, regulators also want to ensure that police and ambulance, and air traffic control, services are able to communicate clearly. The BBC has previously said DAB radio broadcasts are affected by power line technology.

Ofcom said: “Communications networks form an important part of the UK’s national infrastructure, both directly and as an input to other services including safety and security services, utilities and industry (e.g. banking).

“Communications networks are a key aspect on which these services depend for their organisation and operation, and therefore it is important to protect their correct function from undue interference.”

GCHQ is particularly sensitive to interference because part of its role involves monitoring international military radio signals that can be very weak when they reach its receivers.

As well as networking adapters, Ofcom said that in the past two years it had received complaints of electromagnetic interference from TV aerial amplifiers, electrical transformers, high voltage power cables and lighting, among other equipment.

Under the regulator's proposals, those who do not comply with an order to stop their equipment causing “undue interference” face prosecution and fines of up to £5,000 in England and Wales in the most serious circumstances, where lives could be threatened. In Scotland and Northern Ireland the worst offenders face up to three months in prison.

Current legislation blocks the sale of equipment likely to cause interference but Ofcom said the rules do not account for problems once devices are in use caused by deterioration, poor installation, maintenance or improper use. The regulator received 114 complaints of electromagnetic interference last year but had powers to resolve only three, it said.

GCHQ declined to comment on the proposed clampdown. The agency has lobbied for stricter enforcement of anti-interference legislation for several years and in 2011 warned in a rare public intervention, later withdrawn, that power line networking “is likely to cause a detrimental affect to part of the core business of this department”.