New 4G masts in Greenhithe may interfere with television signals, residents are being warned.

Fourth generation mobile services have been switched on in the area giving people faster access to the internet on smartphones and tablets but there is a small chance the signals may interfere with Freeview and cause loss of sound, blocky pictures, freezing or blank screens.

If issues do occur help is available. Set-up under government direction, a company called at800 offers free support to households that rely on Freeview.

Extra support is also available for the elderly and those receiving disability support.

Ben Roome, CEO of at800, said: “We want to ensure that people know it’s our role to fix Freeview interference caused by 4G at 800 MHz, and that there’s no charge for our service.

“If you rely on Freeview for TV, we can send you a filter to fit yourself, free of charge, which fits into the aerial lead connecting to TVs and set-top boxes to block mobile signals. Full instructions are included, and we can provide further advice online and by phone if needed.

“In most instances, fitting the filter will resolve any interference from 4G at 800 MHz, but if this isn’t the case, we may also be able to arrange a follow-up visit from an at800 engineer at no cost, depending on eligibility.”

Cable and satellite TV, like Sky or Virgin, won’t be affected. However, if those viewers also watch Freeview, at800 can provide free filters.

People who live in communal properties should contact at800 and also advise their landlords.

The company can provide free filters to landlords, but property managers are responsible for the cost of fitting them.

The company can be contacted for free on 0808 13 13 800 or at www.at800.tv/contact-us