Every MP who presses the green button to vote "yes" for the Protection of State Information Bill will at that moment take personal responsibility for the first piece of legislation since the end of apartheid that dismantles an aspect of our democracy - a betrayal that will haunt them forever.

The African National Congress has protested against comparisons between this vote and Black Wednesday, the banning on October 19 1977, of The World and the detention of its editor, Percy Qoboza, and staff including Aggrey Klaaste.

But this vote comes amid escalating attacks by the ANC on reporters, newspapers and the freedom of the press. Adoption of the bill could be the first step in a series of attacks, including the creation of the media appeals tribunal mooted by the ANC, that slowly strangle our freedom to know what is being done in our name.

The spreading culture of self-enrichment, either corrupt or merely inappropriate, makes scrutiny by a free media which is fuelled by whistle-blowers who have the public interest at heart more essential than ever since 1994.

If members of the ANC cannot muster the courage to defy their party's leaders and repudiate the bill, it will again - as it was under apartheid - be up to those willing to go to jail for a very long time to expose the abuse of state power.

Covering up corruption is not the primary intention of the so-called secrecy bill - it includes clauses that criminalise its misuse just to avoid embarrassment - but without the means to demonstrate that abuse, the Protection of State Information Bill will be the wall behind which much evil is hidden.

Anyone who leaks a secret, anyone who takes possession of a secret and anyone who publishes a secret will go to jail - potentially for up to 20 years. Motivation will be no mitigation.

Despite repeated assurances that the ANC intends no harm to the media and despite Deputy President Kgalema Motlanthe's apparent acceptance of a public interest clause earlier this month, the party has refused to give judges the right to balance culpability against public good.

Motlanthe has acknowledged that the proposed public interest defence would have to be tested by a judge and almost every submission during parliament's public hearings on the bill called for a last-resort escape clause, but still the ANC has refused.

The bill was presented and withdrawn by Ronnie Kasrils, the minister of intelligence at the time, in 2008.

Then, last year, President Jacob Zuma's cabinet refocused the draft and sent it back to a more pliable parliament with instructions to ensure its adoption.

The ANC did accept more than 120 amendments which greatly improved the original draft. These included a narrowing of the justification for sealing state information and enhanced provisions for oversight and appeal.

But without a public interest clause, this framework for secrecy remains a massive brake on the free flow of information to the people in whose name a tightly protected elite purports to govern.

Opposition parties have declared their intention to oppose the Protection of State Information Bill today. ANC members will be required by the rules of party discipline to be present for the vote and to support it.

We, the editors of the aforementioned South African newspapers, appeal to ANC MPs who will vote today to put the future of your country ahead of your own future in the party and reject this appalling bill.

If not enough MPs have the courage to do the right thing, we urge the cabinet to use the bill's passage through the National Council of Provinces to redraft it with the inclusion of a public interest defence clause.

If it passes through the legislature in its current form, we appeal to President Zuma to exercise his right to submit the bill to the Constitutional Court for ratification before he signs it into law.

If none of these things happens, it will be up to civil society and the political opposition to ask that court to declare it the abomination it is.

Without a triumph of personal integrity over political expediency in the National Assembly this afternoon, this day will mark the beginning of the end of the freedom of information we cherish as a pillar of the constitution that guards our future.