After the UK's credit rating was downgraded by Moodys, veteran Labour backbencher Dennis Skinner told George Osborne that he was a football manager he would have been sacked.
Mr Skinner said: "It's been three years of continuous failure, first a recession, then a double-dip recession, now the relegation of the pound sterling.
"If he'd been a football manager he'd have been out on his neck already.
"Why doesn't he get out!"
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The threat level has been raised to critical by MI5's Counter-Terrorism Analysis Centre.
Prime Minister Theresa May announced the decision from Downing Street.
A man, apparently armed with a small axe and a large stick, was detained close to the event and police cleared the area as a precaution.