Now Hammond turns to the criticisms faced by the intelligence agencies over their handling of Mohammad Emwazi, the extremist known as Jihadi John. As trailed, he attacks those who speak out against them, saying: "We are absolutely clear the responsibility for acts of terror rests with those who commit them. But a huge burden of responsibility also lies with those who act as apologists for them." Our story is here.

tweets:, external recruiting agents - humint as its known - inside AQ/ISIL et al is becoming 'increasingly diffcult' says @foreignoffice philip hammond

tweets:, external That's a relief. Just found the words "long-term economic plan" in Hammond's speech on spies and security. #holdtheline

Spying's getting harder, Philip Hammond tells his audience in Whitehall. "Running agents and delivering intelligence from human sources becomes increasingly difficult as modern technology advances and the opportunities for subterfuge… and clandestine operations are reduced," he says.

As well as state and non-state actors, there are "lone wolves" who launch attacks, too, Philip Hammond says - citing the example of the Lindt cafe attack in Sydney last December. Together these mean the intelligence agencies are facing "the greatest challenge to our collective security for decades".

tweets:, external Russia represents the "single greatest threat to our security" - Philip Hammond

Image source, Reuters

Philip Hammond moves on to the threat posed by Russia. "We are now faced with a Russian leader bent not on joining the international rules-based system… but on subverting it," he says. "We are in familiar territory for anyone over the age of 50." Naturally, the intelligence agencies are responding: "It is no coincidence that all of our agencies are recruiting Russian speakers again."

tweets:, external Hammond claims that critics of the security services are partly to blame for acts of terrorist groups. Sounds like an apologist.

Two years ago, Philip Hammond says, al-Qaeda would have unquestionably been the greatest threat. But now Boko Haram in Nigeria and Islamic State in the Middle East have changed all that. Their growth "simply serves to underline the pace at which the threats to our safety and security from this source are evolving", he says. "Gathering intelligence on these groups represents a fundamentally different order of challenge."

Image source, Getty Images

Philip Hammond sums up the purpose of British intelligence by quoting the Duke of Wellington, the Waterloo victor and former prime minister, who said war was all about "guessing what was on the other side of the hill".

tweets:, external Hammond: UK intelligence agencies have disrupted more than 40 terrorist plots since 2005

tweets:, external Things it's scientifically impossible to get tired of, No 28: Gordon Brown talking about Britishness.

Oversight of the intelligence agencies has been significantly strengthened in recent years, Philip Hammond says. He says the Intelligence and Security Committee, made up of parliamentarians but reporting to the prime minister, is particularly useful.

Philip Hammond begins by reminding his audience that not so long ago it would have been unthinkable for a foreign secretary to acknowledge the existence of Britain's intelligence agencies, let alone give a speech on them. "But we've moved on."

Foreign Secretary Philip Hammond is on his feet at the Royal United Services Institute.

tweets:, external 58 days to the election - @guardian projection: CON 279 seats, LAB 266, SNP 52, LDEM 27

BBC Radio 4 Today

US Ambassador to the UN Samantha Power spoke to Today a short time ago. You can listen again to her full interview here.

tweets:, external Have we reached the long-awaited Tory 'crossover'? Conservatives ahead by four points, according to two pollsters Read more., external

James Robbins
Diplomatic correspondent

Foreign Secretary Philip Hammond will start speaking shortly. He'll say it is time to draw a line under the debate about whether or not the security services need more powers to monitor would-be terrorists. He'll say the debate should be over because nothing should stand in the way of keeping the country safe.

As Ed Balls made clear yesterday, Labour is determined to highlight the severity of the spending cuts he says we're likely to see if the Conservatives form the next government. This morning's Financial Times features a story, external suggesting George Osborne is considering an alternative course. Lower inflation and decent tax receipts could give the chancellor sufficient wiggle-room to avoid having to implement extreme policies which would take us back to 1930s-level spending, the paper says.