PROTESTERS who enter an RAF base in Oxfordshire will be treated as "potential terrorists" and could face up to 51 weeks in jail.

Anyone trespassing at RAF Brize Norton will be breaking a new law which came into force last weekend.

The new offence, passed as part of the Serious Organised Crime and Police Act which set up a British 'FBI', applies to just 13 bases which the Ministry of Defence (MoD) said had been targeted by protesters.

Anti-war protesters have regularly held demonstrations at Brize Norton, which played a role in the military attacks on Afghanistan and Iraq.

An MoD spokesman said it would apply "within the outer perimeter of the site", an area which would be marked clearly with signs.

He added: "At each of the sites, there has been persistent activity by protesters who, by actively trespassing, place themselves at risk of being mistaken as terrorists.

"It has always been difficult for security forces protecting MoD sites to determine the difference between trespasser and potential terrorist.

"This judgement has to be made in a split second and perhaps at times of limited visibility this puts both the trespasser and member of the security force at risk."

As well as a jail sentence, protesters could be fined £5,000.