Right to publish? Guardian editor Alan Rusbridger gets ready to face some uncomfortable questions about the Edward Snowden files

Wilson was deluded and, in the later stages in Downing Street, inclined to paranoia. Rusbridger may have his small paranoias but an unsubstantiated belief in state electronic surveillance is not one of them. He knows, and thanks to the Guardian, everyone knows that big government is bugging millions of people and he has the leaked Edward Snowden files to prove it.

Snowden is the former CIA contractor embraced by the Guardian after he furnished it with the proof about the extent of US spying not only on foreign powers but also its own citizens.

It is unlikely that Rusbridger’s appearance before the committee room will spend much time on the facts of the case. The members know that the US, with the connivance of Britain’s listening post, GCHQ, was electronically bugging and burgling the world; friends and foes alike.

Rusbridger will be answering accusations that the paper damaged national security by printing Edward Snowden's leaked surveillance files, that he conspired with the him to take hundreds of thousands of top secret documents to China and Russia and paid the former CIA contractor to double cross his employees.

These disclosures about the activities of GCHQ eavesdropping and its close cooperation with the US National Security Agency have embarrassed David Cameron and infuriated Conservative MPs, who say the Guardian has compromised national security.

The heads of the UK’s intelligence agencies have also been highly critical about their publication. "They've put our operations at risk," Sir John Sawers, the chief of MI6, told politicians in a public hearing. "It's clear that our adversaries are rubbing their hands with glee – al-Qaida is lapping it up."

John Parker, the MI5 director general, believes that the newspaper revelations are a gift to terrorists and that detecting their communications is a task made even harder.

Sir Iain Lobban, the director of GCHQ, has said his agency had specific evidence of terrorists discussing the leaks in the press in specific terms and moving on to “other communications packages... a direct consequence of what has been referred to in the press".

He told MPs: “Uncovering terrorist cells, revealing people shipping materials or expertise around the world, battling online sexual exploitation of children, all that is in a much weaker place than it was before the revelations.”

Rusbridger and the Guardian are supported by civil liberties groups who say the files show the need for more effective controls over intelligence gathering. Rusbridger has always insisted the paper was right to publish the files and had helped to prompt a necessary and overdue debate.

He believes that those on the security side of the argument wanted to keep everything secret and did not want a debate and that his newspaper had revealed the "extent to which entire populations are now being potentially put under surveillance".

One of the issues that will almost certainly be raised by the committee is a question asked by the head of MI6: what qualifications did the Guardian have when publishing to distinguish between what could undermine security and what was safe?

Hopefully this will be dealt with quickly as there are more sexy details that people want to know and Rusbridger has been boning up on the fine detail of what happened after the paper was approached by Snowden.

His US editor, Janine Gibson, has been flown into the UK for intensive briefing sessions in the editor’s office and every fact from the time Snowden contacted the Guardian will have been gone over in minute detail. The newspaper’s lawyers will also be heavily involved, especially where payments have been made.

The donnish Rusbridger will want the committee to quiz him on an intellectual level – the right to publish and the role of a free press in Britain – but it may well concentrate on the mechanics of the story.

Did the Guardian pay for Snowden’s flights out of the US to China-controlled Hong Kong? While there did it pay for his hotels? What role did the Guardian play in the decision that Snowden would then flee to Russia and is he still being given help with living expenses?

The most crucial questioning could be about the activities of Glenn Greenwald, the reporter behind the story who has recently left the paper. It was his partner, David Miranda, that the UK authorities say was involved in "terrorism" when he tried to carry 58,000 electronic files from Snowden through Heathrow airport.

Miranda was detained and questioned for nine hours by British authorities at Heathrow when he landed there from Berlin to change planes for a flight to Rio De Janeiro, Brazil.

After his release and return to Rio, Miranda filed a legal action against the UK government, seeking the return of materials seized from him. But the government claimed: "Intelligence indicates that Miranda is likely to be involved in espionage activity which has the potential to act against the interests of UK national security. We assess that Miranda is knowingly carrying material the release of which would endanger people's lives.”

Miranda was not charged with any offence but Scotland Yard has opened a criminal investigation. It is understood that the Guardian’s US operation paid his flight with the bill ultimately coming back to London.

Rusbridger will most certainly be asked about the legitimacy of the payment and the decision to use the partner of a reporter to carry such crucial intelligence. Also, the decision of Greenwald to leave the paper, presumably with copies of all the relevant records, raises questions about security. It may be remembered that after the Guardian split with WikiLeaks founder Julian Assange, many of the files that the Guardian had redacted before publication were then published in full.

Immediately after Rusbridger’s hour in the spotlight the commissioner of the Metropolitan Police and another senior officer will be giving evidence about their dealings with the Guardian. It is a pity they cannot be questioned together.