The UK has officially and publicly increased the threat level to 'Severe' from 'Substantial':
...in response to conflicts in Iraq and Syria, Home Secretary Theresa May says. The new alert level rates the risk of an attack on the UK "highly likely", although Mrs May said there was no evidence to suggest one was "imminent".


There is no real explanation for this and the BBC has more context:http://www.bbc.co.uk/news/uk-28986271

The official police press statement:http://www.west-midlands.police.uk/l...s.aspx?id=1570