As N. Gopalakrishnan, a senior member of the Opposition Keadilan Party and former ISA detainee, rose to welcome guests after the dishes of curry and rice were served, helmeted riot police moved in and seized the portable public address system. Officers threatened to fire the water cannons into the diners and arrest everyone if the group refused to disperse.

After a tense stand-off, the party broke up.

Later that night the riot police moved to the home of another Opposition official who was addressing a small group in his front garden. This time the water cannons were fired, arrests were made and people milling in the street were beaten and chased away. It was a scene that has been repeated daily in suburbs, towns and villages across Malaysia over recent weeks.Welcome to the brave new world of Malaysia, where even peaceful political meetings are now banned, where those who dare challenge the ruling order can be sent without trial to solitary confinement for two years on an administrative whim, where anyone who does not support the ruling party can be branded a subversive - and where even eating can be a crime. Welcome to Asia's new police state.

Facing perhaps the greatest threat to his 20-year rule, the Prime Minister, Dr Mahathir Mohamad, has responded with a fierce crackdown on his political opponents that is testing the boundaries of Malaysia's democracy. Over the past few months, the ISA - a law enacted by the colonial British administration to fight communist insurgents more than half a century ago - has been used to lock up the brightest and most outspoken Opposition leaders. In addition, tougher media restrictions have been imposed and a purge of campus activism has seen students arrested and expelled from courses.

Last month the Mahathir Government arbitrarily banned all political gatherings, including those indoors and on private property, launching police on nationwide raids that have seen dozens of people detained and hundreds more harassed and threatened.

In Malacca last weekend, a meeting attended by Abdul Hadi Awang, chief minister of the Opposition-ruled State of Terengganu, was broken up 20 minutes into his speech.

Last week 10 people associated with the biggest Opposition party, the Islamic-based Parti Islam Semalaysia (PAS) - including the son of the chief minister of the PAS Government in Kelantan State, Nik Aziz Nik Mat - were rounded up under the ISA and accused of plotting the violent overthrow of the Government. They were alleged to have received terrorist training from Afghanistan's Taliban militia.

In response to an Opposition outcry that the arrests were baseless and politically motivated, Mahathir warned ominously that he could also have ordered the arrest of the leaders of the Opposition parties: "They can say what they like. If we are politically motivated we will arrest the real leaders such as Nik Aziz, Hadi Awang and [Democratic Action Party leader] Lim Kit Siang, but we did not."

Malaysia's worsening political crisis began with the sacking almost three years ago of Mahathir's deputy and anointed successor, Anwar Ibrahim. Anwar was later jailed for 15 years on charges of corruption and sodomy - charges discredited by international legal observers and the United States Government. His real crime was to challenge the increasingly autocractic leadership of Mahathir and endemic corruption within the ruling United Malays National Organisation.

The harsh treatment of the popular Anwar triggered mass street protests and an electoral backlash that has severely eroded UMNO's once monolithic support in the Malay community.

The last general election, two years ago, saw big swings in support from UMNO to PAS and other Opposition parties, a trend underscored in subsequent by-elections.

Now the Government is facing a serious judicial challenge to its use of the police and public security apparatus in an increasingly desperate attempt to fight the political groundswell - a shift some analysts believe may see UMNO unseated for the first time since independence at the next elections.

A Full Bench of the Federal Court, Malaysia's highest court, this week began hearing an appeal by the six Opposition activists still held since the ISA arrests in April, a case shaping as a landmark test of the use of the ISA and of the independence of the Malaysian legal system, which has long been subjected to intense political pressure.

In a sign of growing alarm within the judiciary at abuses under the ISA, High Court judge Hisahamudin Mohamad Yunus freed two detainees in April, denouncing police for failing to substantiate claims that they were part of a terrorist plot to topple the Government. "Those police officers responsible for the detention of the applicants must wake up to the fact that the supreme law of this country is the Constitution and not the ISA," the judge warned. "To deny the detainees and their families access to one another and to their lawyers for such a long period is cruel, inhuman and oppressive."

There is now growing speculation that the reformist new Chief Justice, Mohamed Dzaiddin Abdullah - whose appointment last year was opposed by Mahathir - is preparing to deliver a judgment that will severely curtail the use of the ISA and ensure greater protection of the rights of detainees, an outcome that may provoke a showdown with the executive.

Before adjourning the hearing to early next month the court dealt an initial blow to the Government by admitting as evidence affidavits by the six detainees. In doing so, a rare window was opened on the often brutal and degrading methods employed by Malaysia's police and security forces against political prisoners.

All the six detailed physical and psychological torture during their detention in solitary confinement, where they were refused contact with their families and legal counsel. All said they were interrogated intensively about their political activities and connections, and abused and threatened for failing to support the Mahathir Government. All insist they were never asked about their supposed involvement in a violent plot against the Government - the reason both police chief Norian Mai and Mahathir gave publicly for their arrests.

Saari bin Sungib, who was arrested after being dragged from a car in front of his distraught wife and children, was subjected to daily interrogation over many weeks: "I was questioned continuously for 38 hours without sleep. The police used five to six investigating officers taking turns among themselves to interrogate me and did not allow me to lie down, or put my head on the table or stand resting on my back and head to the wall."

Another detainee, Hishamuddin Rais, says that during an interrogation, a senior special branch officer boasted that the ISA made the police more powerful than Government ministers, then pointed his hand as if holding a gun and said: "You guys are only demonstrating. If PAS and the Alternative Front [Opposition coalition] wins, we'll all take to the streets with weapons. We are trained and have experience. The Alternative Front won't last a week."

The abuse of the ISA alarms the country's Human Rights Commissioner, Mehrun Siraj, a former dean of the law school at the National University of Malaysia. "They are using it against any sector of society that looks like it is going to oppose the Government and in none of these arrests have the police shown that these people were a threat to national security," she says. "If they have evidence they can charge these people under the penal code."

The president of the Malaysian Bar Council, Mah Weng Kwai, agrees: "There is real cause for concern at what is happening. The frequency of the use of the ISA is getting too close for comfort. This is an oppressive piece of legislation and it should be repealed as soon as possible."

Late last week the Government-appointed Human Rights Commission, known as Suhakam, published a report warning of a serious erosion of civil liberties, accusing police of using high-handed and violent tactics against protesters. "In the past three years, Malaysian civil society has strengthened and the demand for civil and political rights has become louder," the report said.

"This has meant that Government action that infringes the fundamental rights of its citizens no longer remains unchallenged. It is imperative for the Government to respond to the changing political climate and the changing aspirations of Malaysian civil society."

It is a warning that Mahathir Mohamad appears to have no intention of heeding.