Media playback is unsupported on your device Media caption The League is planning to bring up to 100 prosecutions across Wales and England this season.

Pubs in Cardiff and Swansea suspected of showing Premier League football matches illegally using foreign satellites face prosecution, BBC Wales has learned.

In the last four months the Premier League's private investigation firm has visited nearly 200 pubs in south Wales.

The League is planning to bring up to 100 prosecutions across Wales and England this season.

The first will be against The Rhyddings Hotel in Brynmill, Swansea, shortly.

Many south Wales pubs have subscriptions with foreign channels and show Cardiff City and Swansea City's 15:00 GMT Saturday Premier League kick-offs.

These games are unavailable on the Premier League's authorised UK broadcasters - Sky Sports and BT Sport - at the kick-off time.

Copyright law

When we go in and find use of foreign satellite systems we'll give them the opportunity to get rid of that system Dan Johnson, Premier League

By showing the foreign channels, the Premier League believes pubs are probably breaking copyright law.

In 2011 Karen Murphy, a Portsmouth pub landlady, won a court case against the Premier League.

The ruling effectively proved it is legal to buy a TV subscription from anywhere in the EU.

However, when a pub or club uses such a subscription to show Premier League football matches, it is breaking copyright law if the League's logo is shown in on-screen graphics, or if the League's anthem is heard before kick-off or at half time.

Tom Richards, a barrister specialising in copyright law, said it was unlikely a pub could screen the games without breaching Premier League copyright.

"The Premier League owns the copyright in its logo, in its anthem and in other bits of sound recording and artwork which are superimposed on any feed of a Premier League match," he said.

"If you play those in a pub without the Premier League's consent that's copyright infringement in the law of copyright.

"Technically speaking, there is a loophole.

"If you could separate out the copyrighted content, such as the Premier League logo, from the match footage, then in theory you wouldn't be infringing copyright.

Image caption Pubs screening matches illegally will be warned first

"In practice it's rather doubtful whether that can be achieved because the Premier League - you can be confident - will make it as hard as possible to separate out the protected from the unprotected content."

Some pubs try to use this loophole by blocking out graphics of the Premier League logo.

But the League says its private investigation firm, ID Inquiries, has not come across any "masking technology" that would stop it taking action against a pub.

So far this season ID Inquiries has visited 195 pubs in the Cardiff and Swansea areas and is planning legal action against "a small number of them".

'Black spots'

Dan Johnson, the Premier League's director of communications, said: "BT Sport and Sky Sports invest huge amounts of money in the Premier League and that then is in turn invested by the clubs in new stadia, developing players, acquiring players, the whole range of things that make Premier League football so popular.

"So anything that damages the ability of broadcasters to invest in that has the potential to damage the ability of the clubs to invest in that.

"With the advent of Cardiff and Swansea being in the Premier League clearly the interest in Premier League football has gone through the roof in south Wales.

"So, it becomes an area of interest and you can go round the country and you can see these blackspots where Premier League football is of great interest, and people will try and utilise that interest to their advantage, including pubs and clubs.

"We want to help pubs, we want to help educate licensees, and when we go in and find use of foreign satellite systems we'll give them the opportunity to get rid of that system."

"So if in the first instance - they say 'we hear you, we'll get rid of this system and we'll get a legitimate one' - they will face no further action and we don't want to be going round the country prosecuting pubs and licensees.

"However if they choose not to, they face the very real prospect of prosecution."

Mr Johnson says the League expects to bring up to 100 prosecutions this season across Wales and England.

The action against The Rhyddings Hotel in Swansea is the League's first prosecution since the Karen Murphy case and is expected to be heard in the next few weeks.