Two universities have warned lecturers that if they go on strike they will be partly responsible for student failures and could face legal action.

In emails seen by the Daily Telegraph, staff at both Reading University and City University, London, were told that by opting to take part in industrial action, due to start on Thursday, they could be liable for damages if students sue for breach of contract.

The threats were likened to “bullying” by the University and College Union.

Teaching staff at more than 60 universities are due to begin a wave of walkouts if a bitter dispute over pensions is not resolved, affecting more than one million students.

The scale of the strike action is understood to be unprecedented on British campuses.

But it will result in cancelled lectures, tutorials and seminars which could have a significant impact on students who pay £9,000 annual tuition fees.