London Underground is reviewing its terror attack procedures for staff amid an increase in security measures across the capital, IBTimes UK has learned.

The move comes as the Metropolitan Police deploys 600 extra armed police officers in a bid to protect people against attacks and following a string of terrorist incidents across Europe.

"The safety and security of our customers and staff is our top priority," a Transport for London spokesman told IBTimes UK.

"We work closely with Police and Government colleagues, who have advised us and other train operating companies to prepare guidance for our staff about what to do in the event of a gun attack on a train.

"We have been working closely with our staff and trade unions over the past few months to shape the guidance that we will give to our staff."

Management and the trade unions have reportedly met to discuss the threat and response to a so-called 'active shooter' incident on a train. A draft proposal has been put forward that in some instances drivers should open train doors when beyond a platform in a bid to let passengers escape and limit casualties, according to the RMT Union.

Muhiddin Mire, 30, was given a life sentence on Monday (1 August) after he attempted to behead a London commuter and threatened four others with a knife on 5 December, 2015.

Mire, who had a history of mental illness, is said to have carried out the attack at Leytonstone Tube station, east London, in response to the UK's bombing campaign against Syria. Police also discovered he downloaded so-called Islamic State (Isis) propaganda in the days before the attack.

Images of murdered Fusilier Lee Rigby were also found on his phone, as well as those of the British Isis executioner known as Mohammed 'Jihadi John' Emwazi. The London transport network was also targeted on 7 July, 2005, when a series of suicide bomb attacks left 52 dead and hundreds injured.

The current threat level for international terrorism in the UK is 'severe', which means an attack is a 'highly likely'. The level was upgraded from 'substantial' in August 2014 and is determined by the Joint Terrorism Analysis Centre (JTAC), while MI5 is responsible for setting the threat levels from Irish and other domestic terrorism.