* Ban: any attack against peaceful protesters unacceptable
* Ban urges restraint, dialogue to ensure orderly transition
(Releads with fresh comment from Ban, changes dateline)
By Adrian Croft
OXFORD, England, Feb 2 (Reuters) - The head of the United Nations on Wednesday urged sweeping reforms in Egypt in response to mass protests against President Hosni Mubarak's 30-year rule, and warned against attacks on demonstrators.
"The protests reflect the great frustration of the Egyptian people about the lack of change over the past few decades. This discontent calls for bold reforms, not repression," U.N. Secretary-General Ban Ki-moon said during a visit to the English city of Oxford.
Speaking earlier in London, he said: "Any attack against peaceful demonstrators is unacceptable and I strongly condemn it."
Supporters of President Hosni Mubarak, throwing petrol bombs, wielding sticks and charging on horses and camels, fiercely attacked demonstrators in Cairo after the army told protesters to clear the streets.
"I am deeply concerned by the continuing violence in Egypt. I once again urge restraint to all the sides," Ban said after meeting British Prime Minister David Cameron in London.
He added that for the last decade, the United Nations has been warning about the need for change in Arab countries.
"We should not underestimate the danger of instability across the Middle East."
"It is important at this juncture to ensure that an orderly and peaceful transition should take place. I urge all the parties to engage in such a dialogue ... without further delay," he said, adding that the United Nations stands ready to support any reform effort by Egypt and any other Arab countries. (Additional reporting by Olesya Dmitracova and Stefano Ambrogi in London; editing by Elizabeth Fullerton)