Staff strike over pensions at England's universities
Strike action has been hitting some of the older universities across England as lecturers walked out in a dispute over pensions.
Some 47 universities - including Cambridge, Bristol, Manchester and Leeds - face the walk-outs by members of the University and College Union over changes to their pension scheme.
The union said employers had refused to come to the negotiating table.
The Employers Pensions Forum said the strike was damaging to students.
And students at University College London have now occupied the university's Registry in support of staff out on strike.
Tuesday's walk-outs followed strikes by UCU members in Scotland, Wales and Northern Ireland in the past few days over the same pension scheme - the Universities Superannuation Scheme.
The UCU said the dispute centred on attempts to raise the retirement age, increase contributions and end the final salary element of the scheme for new joiners.
A UK-wide strike action is set to take place on Thursday when members on another pension scheme join the walk-out.
UCU general secretary Sally Hunt said: "University staff really value their pension rights and have made it clear from the start of this dispute that if the employers were not prepared to negotiate then we would be left with little option but to take strike action.
"Strike action is always a last resort and we have always wanted to meet the employers to avoid widespread disruption.
"However, both sides had to be prepared to go that extra mile and the employers clearly weren't. I share the frustration that students must be feeling at the employers' intransigence."
Professor Brian Cantor, chairman of the Employers Pensions Forum, said university employers were disappointed at UCU's decision to take industrial action over the scheme.
"An enormous amount of work has gone into the development of the package of reforms to USS with representatives from EPF, UCU and the USS Trustee Board playing pivotal roles in finalising moderate changes of benefit to all.
"The changes are in response to the increasing costs to the scheme from improved longevity."
He added that the retention of a final salary pension for all existing USS members was an exceptionally good benefit and that the career average scheme for future employees was in line with what looks set to become the norm in all sectors.