Britain's Supreme Court heard its first case Monday — an appeal by five terrorism suspects who say the British government has overstepped its power by freezing their assets without a conviction.

For hundreds of years, Britain's highest court of appeal had been the Law Lords, a group of justices who were part of the House of Lords in Parliament. The decision to create a Supreme Court was meant to emphasize the separation of governmental powers, even if the change is largely in name and location only.

The 12 justices are no longer part of the House of Lords but are still Britain's most powerful judges. Shedding their past image, they wore no wigs, no robes and sat in a new courtroom equipped with cameras and microphones for their first hearing. Recording had been prohibited in most cases.

The court's first case was chosen because it touched on terrorism and the government's ability to freeze assets without due process.

The suspects say they have to ask for permission to access their money to buy groceries and pay other living expenses. Their families are prohibited from giving them money.

A High Court judge ruled last year that Britain's finance department had no right to freeze their bank accounts, but that decision was overturned by the Court of Appeal.

Tim Owen, representing three of the men, said the case raised questions over "blank check" legislation where the government can make laws without parliamentary debate. He said a balance needed to be struck between national security concerns about terrorism and fundamental human rights and access to the courts.

All but one of the suspects were granted temporary anonymity until another hearing Thursday. After a media challenge that included The Associated Press, the justices lifted the anonymity order against Mohammed al-Ghabra, whose name had already been in the public domain.

The U.S. Treasury alleged in 2006 that al-Ghabra had helped people travel to Pakistan to meet with senior Al Qaeda leaders and to participate in terrorist training camps. He was also alleged to have provided "material and logistical support" to other terrorist organizations in Pakistan. Britain also designated him an alleged financier of terrorist organizations.

Neither Al-Ghabra, a 29-year-old who was born in Syria and later obtained British citizenship, nor any of the others have ever been convicted.

The men's assets were seized based on two U.N. Security Council resolutions that imposed sanctions on people alleged to be funding terrorism.

Owen said whether the government was lawfully entitled to impose such restrictions depended on an analysis of the U.N. act.

He said it was the first time the courts had had the chance to look at the questions and that the government had used powers to impose "a draconian, intrusive regime which destroys the individual's power to live any sort of normal life without any conviction in a court."

More than 50 people living in Britain are believed to be on the Treasury sanctions list.

The hearing — taking place in a neo-Gothic court room across from Britain's Houses of Parliament and Big Ben — is expected to last throughout the week.

If the justices decide in favor of the men, the decision could have far-reaching implications for the government's ability to freeze assets in the future.

If the justices reject the appeal, the men may be able to take the case to the European Court of Human Rights.

In 2004, the Laws Lords ruled that the government could not indefinitely hold foreign terrorist suspects without charge, which was a blow to the government.

Unlike the U.S. Supreme Court, which can strike down laws it deems unconstitutional, Britain's Supreme Court can prompt lawmakers to call for reforms but it cannot strike down laws since the U.K. has no written constitution.