LONDON (AFP) - Britain expressed concern Sunday about the escalating crisis in Pakistan but welcomed the government's promise to appeal a court ruling barring PML-N Quaid Nawaz Sharif and his brother Shahbaz Sharif from contesting elections and holding any public office. "The risks to security are real and pressing but so is the need for political unity and progress," British Foreign Secy David Miliband said. He praised President Zardari's vow to appeal the court ruling on Sharifs and resolve a row over sacked judges. "This is an act of statesmanship from President Zardari and PM Gilani that recognises the urgent needs of the country," he said. "These announcements need to be followed by commitments from other parties and real talks about the future." Miliband urged all parties to "unite in common cause against Pakistan's true enemies - terrorism, poverty and political instability". He also called on all those involved in the banned mass protest that Nawaz was leading to the capital to ensure it was peaceful. "I remain concerned about the arrests of opposition supporters, which is not an appropriate response to legal public protest," he said.