The biggest upward contribution to the new inflation rate of 2.8% has been increases in gas and electricity bills, as well as price changes for recreational goods, according to the Office for National Statistics.
Also contributing were prices for motor fuels and air transport.
The largest downward contributions came from small price increases for food and drinks.
More top news
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.