Hackers have been ruled out as the cause of the fault that shut down the UEA's IT and phone network for more than 40 hours.

The system went down at about midnight on Monday but the website was back online at about 4pm today and more services were expected to be up and running by tomorrow morning.

It was particularly bad news for students who have coursework and exams to finish before the end of the week when they break up for Christmas.

With the system down students were facing difficulties in completing and submitting assessed work and accessing timetables.

Pro vice chancellor academic, Tom Ward said the problems started at midnight on Monday and the system was working intermittently on Tuesday, before it collapsed completely today.

Mr Ward said: 'It took a while before we were able to know that it was not something attacking us and a denial of service. That was a question initially, but we are very confident it is not.

'It seems to be an unexpected and catastrophic hardware fault in, what I've been told, is the network core.

'We are extremely concerned above all about our students who have course work tests and deadlines.

'We are doing our best to keep in communication with them through Facebook and Twitter.

'We appreciate how stressful and unpleasant it is for the students. It's a really bad business and we are extremely sorry.

'The students' union has been extremely helpful, as its website is separate from ours.'

Posters were placed around the campus apologising for the inconvenience and disruption and urging students to consult their teaching offices for further advice.

Students Danielle Reeve, 20, and Bethany Moore, 19, are both studying for degrees in public service at the UEA and at City College Norwich.

Danielle said: 'It is causing a bit of chaos. We cannot transfer stuff through emails and cannot send anything through hotmail. It's affecting getting work to our lecturers to look at. I know that the deadline for work in one subject has been extended.'

Other students complained they were unable to access the internal UEA's portal, and another student was confused about where to go for a maths exam as he could not call the university or access its website.

The UEA said further updates would be made on Facebook and Twitter - www.facebook.com/ueaofficial and www.twitter.com/uea_news.