Prof Rosa Freedman, 35, of Reading University, said an anonymous caller had also found her personal mobile phone number and made a series of 'harassing' calls to her overnight. Undated photo

A law professor says she has been threatened with rape and murder and forced to hide behind trees to avoid transgender-rights activists who allegedly drenched her office door in urine.

Prof Rosa Freedman, 35, of Reading University, said an anonymous caller had also found her personal mobile phone number and made a series of 'harassing' calls to her overnight.

Women's rights expert Prof Freedman is among a number of academics that have called for sex and gender to be defined differently in law, which would mean transgender women could be barred from entering 'women's only' toilets or prisons.

Prof Freedman believes her abusers could have been buoyed by academics calling her a 'bigot' and 'transphobic' over her views on social media.

She has called police and said she was concerned the attacks could escalate after reporting the attack on Twitter in the early hours of this morning.

She wrote: 'I found my office door covered in urine, including some that had seeped under the door, and I spent time cleaning it up because I could not bear the smell or the shame of what had happened.

'Last week I discovered criminal damage explicitly encouraging me to leave the University.'

Professor Freedman has called police and said she was 'concerned' the attacks could escalate after reporting the attack on this Twitter thread in the early hours of this morning

Speaking today, she said: 'There's been an awful lot of abuse online - abuse, harassment from students - for a number of academics, not just me.

'Last night someone seems to have accessed my mobile phone number and has been calling it through the night.

'When things are done anonymously we all feel the only way to fight back is to go public about it.'

Asked if she was concerned the attacks could escalate, she said: 'It's concerning, that being said there's a student society on campus who are strongly opposed to everything I say - but they've come out quite strongly today that they condemn this type of behaviour.'

She added: 'This started over the last year for many academics that speak about sex and gender being two separate things.

'I've been on Women's Hour in the last couple of weeks. Yesterday we had a women's rights meeting organised by Women's Place UK - it was in Reading and a couple of others were speaking.

'Some students tried to shut the meeting down and have a protest so that meeting may have started it.

The academic described how urine had been smeared on her office door by activists trying to stop her from speaking about her work

'I think what's really happened is that over the last few months there have been a few academics who have really attacked women's rights activists.

'There have been deeply personal attacks. These academics call us words like 'bigots' and 'transphobic'. There's a fine line.

'We live in a liberal democracy and academics, their role and responsibility is to address difficult and timely issues in a reasonable manner and I've remained responsible and respectful in these discussion and will continue to do so and expect that will be extended back to me and abuse and harassment will not be tolerated.'

A Reading University spokesperson said: 'The University is aware of these alleged incidents and we are investigating them.

'The safety of students and staff is our top priority and we do not tolerate any form of harassment or intimidation, but until we know more details we cannot say anything further.'

A Reading University spokesperson said: 'The University is aware of these alleged incidents and we are investigating them.' Pictured: The university's main library in an undated image