Donald Trump has made a habit of using his Twitter account to comment on world events since he became US president, but he has been uncharacteristically quiet over Russia’s alleged use of a nerve agent on British soil.

Last year’s Westminster attack, Manchester Arena bomb, London Bridge attack and Parsons Green bomb all became topics of Mr Trump’s famous tweet storms, sometimes within hours of the incident itself while police were still on the scene.

He was also quick to respond to incidents across Europe, Egypt and the US over his first year, offering condolences to the victims and messages of support for leaders of the countries concerned.

But of the major UK security incidents involving counter terror police since he took office, Mr Trump has tweeted about all except two: the Finsbury Park terror attack and the poisoning of Sergei Skripal.

Here is how each incident panned out, and how Mr Trump responded.

– Westminster attack

On the afternoon of March 22 2017,  Khalid Masood, a 52-year-old born Adrian Elms in Kent, drives a car into pedestrians on Westminster Bridge before entering Parliament grounds and fatally stabbing a police officer. Massood is shot dead by police. Six people, including Masood, are killed.

Police declare the incident a terrorist attack.

Almost 11 hours later, Mr Trump tweets: “Spoke to U.K. Prime Minister Theresa May today to offer condolences on the terrorist attack in London. She is strong and doing very well.”

– Manchester Arena bombing

Salman Abedi, a 22-year-old born in Manchester, detonates a homemade nailbomb as people leave an Ariana Grande concert at Manchester Arena. Twenty-two people are killed.

Police declare the incident a terrorist attack.

The following day, Mr Trump tweets: “We stand in absolute solidarity with the people of the United Kingdom.”

– London Bridge attack

Three attackers drive a van into pedestrians on London Bridge before stabbing multiple people in the street and nearby pubs and restaurants. Khuram Butt, a British citizen born in Pakistan, Rachid Redouane, a failed asylum seeker born in Morocco or Libya, and Youssef Zaghba, born in Morocco, are all shot dead by police. Eight people are killed.

Police declare the incident a terrorist attack.

Within hours, while police are still actively dealing with the incident, Mr Trump tweets: “Whatever the United States can do to help out in London and the U.K., we will be there – WE ARE WITH YOU. GOD BLESS!”

The next day, on June 4, Mr Trump continues his monologue, attacking London Mayor Sadiq Khan over his handling of the incident.

“At least 7 dead and 48 wounded in terror attack and Mayor of London says there is “no reason to be alarmed!”” he tweets at 12:23 pm UK time.

Twenty minutes later he tweets again: “Do you notice we are not having a gun debate right now? That’s because they used knives and a truck!”

The following day, on June 5, Mr Trump continues his verbal attack on Sadiq Khan.

“Pathetic excuse by London Mayor Sadiq Khan who had to think fast on his “no reason to be alarmed” statement,” he tweets. “MSM is working hard to sell it!”

– Finsbury Park attack

Darren Osborne, a 47-year-old from Cardiff, drives a van into worshippers leaving a mosque in Finsbury Park, London. One person is killed.

Police declare the incident a terrorist attack.

Mr Trump does not comment on the incident.

– Parsons Green bomb

A bomb fails to detonate properly on a commuter train at Parsons Green station, London. The main suspect, Ahmed Hassan, is arrested the following day. His trial is ongoing. No one is killed.

Police declare the incident a terrorist attack.

Within hours of the bomb, before any suspect has been identified, Mr Trump sends two tweets directly commenting on the incident.

“Another attack in London by a loser terrorist,” reads the first. “These are sick and demented people who were in the sights of Scotland Yard. Must be proactive!”

Trump tweets: “Loser terrorists must be dealt with in a much tougher manner.The internet is their main recruitment tool which we must cut off & use better!”

That evening, Mr Trump tweets a statement: “Our hearts & prayers go out to the people of London, who suffered a vicious terrorist attack….”

– Skripal poisoning

Former Russian spy Sergei Skripal and his daughter Yulia are found unconscious on a park bench in Salisbury on Sunday March 4, although their identities are not made public until the following day.

Over the following week, the pair are revealed to have been poisoned using a nerve agent and counter terror police take over the investigation as politicians and media speculate about Russia’s involvement. A statement from the US is conspicuous in its absence.

On March 12, a week after the investigation started, Theresa May tells MPs the nerve agent is of Russian origin, adding it is “highly likely” Russia is responsible.

White House press secretary Sarah Huckabee Sanders issues a statement of support for the UK before US secretary of state Rex Tillerson says he has “full confidence in the UK’s investigation and its assessment that Russia was likely responsible for the nerve agent attack”.

Mr Trump sacks Tillerson in a tweet the next morning and later tells reporters outside the White House: “as soon as we get the facts straight, if we agree with them, we will condemn Russia or whoever it may be.”

He speaks to Theresa May by phone that evening, reportedly offering his full support, but has yet to issue any personal statement on the matter.

On the topic of Sergei Skripal and the Russian nerve agent, the US president’s usually rambunctious Twitter account remains silent.