Mr Bernanke is also expected to reassure investors that the $85 billion a month bond buying scheme can be stepped up again, even after the brakes are applied, in an attempt to ease market concerns that America is about to embark on a total withdrawal from QE.

Markets have experienced an unusually volatile few weeks, following the Fed chairman's warning last month that it could start winding down the programme "in the next few meetings" if economic data continued to show that America was well on the road to recovery.

The spike in margin debt was rapidly followed by a horrifying stock market crash. Well guess what? It is happening again. In April (the last month we have a number for), margin debt rose to an all-time high of more than 384 billion dollars. The previous high was 381 billion dollars which occurred back in July 2007. Margin debt is about 29 percent higher than it was a year ago, and the S&P 500 has risen by more than 20 percent since last fall.

The stock market just continues to rise even though the underlying economic fundamentals continue to get worse. So should we be alarmed? Is the stock market bubble going to burst at some point? Well, if history is any indication we are in big trouble. In the past, whenever margin debt has gone over 2.25% of GDP the stock market has crashed. That certainly does not mean that the market is going to crash this week, but it is a major red flag.

Editors were asked not to publish information that may "jeopardise both national security and possibly UK personnel" in the warning issued on 7 June, a day after the Guardian first revealed details of the National Security Agency's (NSA) secret Prism programme.

The D notice, which was marked "private and confidential: not for publication, broadcast or use on social media", was made public on the Westminster gossip blog, Guido Fawkes. Although only advisory for editors, the self-censorship system is intended to prevent the media from making "inadvertent public disclosure of information that would compromise UK military and intelligence operations and methods".

The warning was issued by defence officials in the UK as the BBC, ITN, Sky News and other newspapers and broadcasters around the world covered the surveillance revelations disclosed by the NSA whistleblower Edward Snowden. The leaks, reported extensively in the Guardian and also the Washington Post, have made headlines on both sides of the Atlantic for more than a week.

The folks running the NSA have already shown that they are willing to flat out lie to Congress, and Barack Obama doesn’t exactly have the greatest track record when it comes to telling the truth. These are men that play word games and tell lies for a living. So it would be unrealistic to expect them to come out and tell us the unvarnished truth about what is going on.

That is why it is so important that whistleblowers such as Edward Snowden have come forward. Thanks to them and to the brave journalists that are willing to look into these things, we have been able to get some glimpses behind the curtain. And what we have learned is not very pretty.

The Vatican and the Lutheran World Federation (LWF) presented a report in Geneva admitting both were guilty of harming Christian unity in the past and describing a growing consensus between the two churches in recent decades. The 500th anniversary of Martin Luther's 95 Theses, the doctrinal challenge that launched the Protestant Reformation, will be the first centenary celebration in the age of ecumenism, globalization and the secularization of Western societies.

"The awareness is dawning on Lutherans and Catholics that the struggle of the 16th century is over," the report said. "The reasons for mutually condemning each other's faith have fallen by the wayside." They now agree belief in Jesus unites them despite lingering differences, it said, and inspires them to cooperate more closely to proclaim the gospel in increasingly pluralistic societies.

"This is a very important step in a healing process which we all need and we are all praying for," LWF General Secretary Martin Junge said at the report's presentation in Geneva. "The division of the church is something we cannot celebrate but we can see what is positive and try to find ways towards the future together," said Cardinal Kurt Koch, head of the Vatican's department to promote Christian unity.

They currently vow to "to love my God, to serve my Queen and my country". The new oath drops the reference for the first time since Guides began in 1910 and will see them promise to "be true to myself and develop my beliefs". The revised wording from September will also see members of the 540,000-strong organisation promise "to serve the Queen and my community".

The promise has been changed 11 times in the organisation's history, most recently in 1994 when the long-standing phrase "duty to God" became "to love my God" and "serve the Queen" was supplemented with "and my country".

In December last year, the UK Scout Association announced its own consultation to see if its members would support an alternative Scout Promise for atheists, who are unwilling to pledge a "duty to God". And in July 2012, the Girl Guides in Australia dropped their allegiance to both God and the Queen, agreeing to serve their community and be true to themselves instead.

On Tuesday, Barack Obama is coming to Germany. But who, really, will be visiting? He is the 44th president of the United States. He is the first African American to hold the office. He is an intelligent lawyer. And he is a Nobel Peace Prize laureate.

But is he a friend? The revelations brought to us by IT expert Edward Snowden have made certain what paranoid computer geeks and left-wing conspiracy theorists have long claimed: that we are being watched. All the time and everywhere. And it is the Americans who are doing the watching. On Tuesday, the head of the largest and most all-encompassing surveillance system ever invented is coming for a visit. If Barack Obama is our friend, then we really don't need to be terribly worried about our enemies.

What, exactly, is the purpose of the National Security Agency? Security, as its name might suggest? No matter in what system or to what purpose: A monitored human being is not a free human being. And every state that systematically contravenes human rights, even in the alleged service of security, is acting criminally.

He announced the start of formal negotiations on a trade deal worth hundreds of billions of pounds, aimed at boosting exports and driving growth. Mr Cameron said a successful agreement would have a greater impact than all other world trade deals put together.

The talks were announced ahead of the G8 summit in Northern Ireland. US President Barack Obama said the first round of negotiations would take place in Washington in July. They aim to conclude by the end of 2014.

“We have agreed to push the sides of the Syrian conflict to come to the negotiating table at the international Geneva conference,” Putin said. “On some points, we still have a different stance, but we are united by an aspiration to prevent violence, to put an end to the growing number of victims, to solve the problem by peaceful means, including through negotiations at the international conference at Geneva,” the Russian President added.

President Obama conceded that he has a “different perspective” on Syria than his Russian counterpart, but confirmed that both countries have a shared interest in stopping the violence and “securing chemical weapons” in Syria. “We do have differing perspectives on the problem but we share an interest in reducing the violence, securing chemical weapons and ensuring that they're neither used nor are they subject to proliferation,” Obama said. “We want to try to resolve the issue through political means if possible.”

Hasan Rowhani's first post-victory news conference was a study in what may make his presidency tick. Rowhani may be hailed as a force for change, but he also appears to carry a deep and self-protective streak of pragmatism. He knows he can only push his views on outreach and detente as far as allowed by the country's real powers, the ruling clerics and their military protectors, the Revolutionary Guard.

Many of Rowhani's statements reflected these boundaries, which could later expand or contract depending on how much the theocracy wants to endorse his agenda. When he appealed to treat "old wounds" with the US, he also echoed the ruling clerics' position that no breakthroughs can occur as long as Washington is seen as trying to undermine their hold on power. Rowhani's urging for greater "nuclear transparency" as a path to roll back sanctions was also punctuated by a hard-liner stance: No chance to stop the uranium enrichment labs at the heart of the stalemate with the West and its allies.

"You can make any kind of promises you want," said Merhzad Boroujerdi, director of the Middle East Studies program at Syracuse University. "At the end of the day, it's the ruling clerics that decide whether they go anywhere."

The government raised the threat of putting soldiers on the streets after a weekend of violent clashes prompted by the eviction of campers occupying Istanbul's Gezi Park, the epicentre of the protest movement. Police "will use all their powers" to end the unrest, Bulent Arinc, deputy prime minister, said in a televised interview. "If this is not enough, we can even utilise the Turkish armed forces in cities."

The deployment of the military, the self-described guardian of the secular state, would mark an escalation of a crisis posing the biggest challenge yet to Recep Tayyip Erdogan's Islamic-rooted government. The US and other Western allies have widely criticised Erdogan's handling of the crisis, undermining Turkey's image as a model of Islamic democracy.

German Chancellor Angela Merkel, for her part, urged Turkey to respect democratic freedoms and said the police response to the protesters "was much too harsh". "I am in any case shocked," she told RTL television on Monday.

They will also try to work out why this spring was the coldest in 50 years - with a UK average of 6C (42.8F) between March and May. The Met Office hopes the meeting will identify new priorities for research. Over the past three years, British weather records have been under increasing pressure. The big freeze that gripped the UK in December 2010 saw the lowest temperature for the month in 100 years.

Even the buzz of the London Olympics could not disguise the washout that was last summer, the second wettest for the UK since records began. Puzzled by these events, scientists from across the UK are meeting at the Met Office in Exeter to try to understand the reasons behind this run of what they term, "unusual seasons".

However a discussion of man made climate change is unlikely to feature. "This meeting isn't looking at climate change, it's looking at climate variability in recent seasons," said Dan Williams.

British Prime Minister David Cameron, who chairs the G8 summit in Northern Ireland, acknowledged there was “a big difference” between the positions of Russia and the West on Syria. Moscow said it would not permit no-fly zones to be imposed over Syria.

US President Barack Obama will meet Putin later on Monday and, in what could be a frosty encounter, will try to convince the Kremlin chief to bring Assad to the negotiating table. Putin has warned the West it risks sowing turmoil across the Middle East by arming the Syrian rebels.

Other Western leaders criticized Russia, Assad’s only big-power ally, for delivering arms to Assad while the rebels – whom Putin described on Sunday as cannibals who ate their enemies’ intestines – perished.