A legal loophole allowing viewers to watch BBC programmes on the iPlayer without paying for a TV licence is about to close. From 1 September, viewers will have to pay the £145.50 annual licence fee to watch any BBC content on the iPlayer, including live and on-demand programmes.

The rule applies to every way in which the iPlayer can be watched, including through a Smart TV, laptop or computer, tablets and mobile phones, TV boxes from the likes of Sky and Virgin Media, games consoles, streaming devices like the Apple TV and Amazon Fire TV, and any other device which is used to watch television.

The BBC has said the rule also applied to content which is shown exclusively online, such as BBC Three, which recently became iPlayer-only.

"From 1 September 2016 you will need to be covered by a TV licence to download or watch BBC programmes on demand, including catch up TV, on BBC iPlayer," the broadcaster said. "This applies to any device and provider you use."

If you are caught watching without one you can be prosecuted and fined up to £1,000 plus legal costs and possible compensation. The maximum fine is £2,000 in Guernsey and £500 in Jersey.

Viewers who already have a licence do not need to do anything. They are covered to watch BBC content whenever and however the like. Those eligible for a free licence are also covered.

A licence is not needed if you only plan to watch the Welsh language S4C TV channel, or to listen to BBC radio stations, on the iPlayer. It is also not required to watch on-demand content from other services, such as ITV Hub, All 4, Demand 5, Sky Go, Netflix and others.

If you are away from home or travelling abroad, your TV licence will cover you to watch BBC content, including iPlayer live streaming and downloads, as long as the device you are using is not plugged into the mains electricity at any address other than your own, for which you pay the licence. Although iPlayer programmes cannot be streamed abroad, downloaded content still works.