On 22 May 2017, at least 22 were killed after a bombing occurred following a concert by Ariana Grande in the most deadly terrorist attack on British soil since 2005. After a COBRA meeting, UK Prime Minister Theresa May announced that the UK's terror threat level was being raised to 'critical', its highest level. By raising the threat level to "critical", Operation Temperer was started, allowing 5,000 soldiers to replace armed police in protecting parts of the country. BBC's Frank Gardner said that the first deployment of troops is expected to be in the hundreds.