Picket lines are trespassing, the University of Birmingham has told its striking lecturers, prompting a furious backlash from academics and students.

Thousands of lecturers at 60 universities are staging an eight-day walkout this week in a row over pay, working conditions and pension cuts which is set to affect more than one million students.

But in a briefing email to Birmingham university employees on Nov 22 ahead of the strike action, provost and vice-principal Tim Jones reportedly claimed that the campus is 'private land' and anyone picketing is trespassing.

His comments have provoked outrage, with hundreds of people signing a petition calling on him to withdraw his "threats".

Members of the University and College Union (UCU) branded his reaction "disgraceful, heavy-handed and counterproductive".

More than 800 people - including 10 law professors - have signed a petition calling on Mr Jones to withdraw his claims or provide legal justification for them, and start engaging with demonstrators about how they can express their views on campus.

The right to hold peaceful demonstrations on university campuses is protected by the Trade Union and Labour Relations Act 1992.