The UK Foreign Secretary William Hague rejected a claim the government was "softening" its approach to Iran.
Speaking in the parliament, Mr Hague described the UK as "absolutely relentless" in its efforts to defeat terrorism around the world and added: "I can assure you that there is no softening of any of our policies in relation to Iran.
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The 23-year-old was held on suspicion of doing an act likely to cause an explosion to injure or damage property, and endangering safety.
Three men died on the track between Brixton and Denmark Hill in south London.
This year 21 black-tailed godwits have been released into the wild after being reared in captivity as part of a project to boost breeding nu