Buckingham Palace on lockdown after man arrested for throwing suspected shotgun cartridges on the...

A man who 'threw shotgun cartridges' into the grounds of Buckingham Palace was arrested on suspicion of possessing a weapon.

Met Police detained the man at around 7pm today after he approached the gates of the palace in central London as Coronation rehearsals took place.

Witnesses said the man, believed to be in his 30s, was seen throwing a 'number of items' in the residence grounds before he was arrested and detained. Police later carried out a controlled explosion on a suspicious bag as a precaution. 

A witness told The Sun that the suspect had stationed himself outside the palace over the 'last few nights' and was heard shouting: 'I'm going to kill the King.'

Police say they are not currently treating the incident as terror-related. It is understood it is being treated as an isolated mental health incident.

Buckingham Palace confirmed the King and Queen were not in residence when the incident occurred. But a Royal spokesperson would not answer whether any other relatives or family members were there when it unfolded.

Police carried out a controlled explosion on the suspect's bag as a precaution. Officers are pictured at the scene, by the bag

Police stand guard outside Buckingham Palace after a man was arrested this evening on suspicion of possessing a weapon

Police say they are not currently treating the incident as terror-related. It is understood it is being treated as an isolated mental health incident. Officers are pictured at the scene

Buckingham Palace is on lockdown after a man threw suspected shotgun cartridges on the ground outside the royal residence - just days from Charles' coronation

Troops were seen rehearsing for the upcoming Coronation while the incident unfolded

The Metropolitan Police said officers arrested a man around 7pm tonight after he approached the Palace gates

Police cordoned off the area outside the palace after the suspect began targeting the royal residence. 

Met Police chief superintendent Joseph McDonald said officers 'worked immediately to detain the man' - who is currently in custody.

A witness alleged that officers 'jumped' on the man 'as soon as he placed the bag on the ground'.

'They were shouting at him "get down on the floor,"' the witness told The Sun, adding that it was 'astonishing' that the man was even able to get that close to the Palace with the Coronation just days away.

Royal super fans who are camped along The Mall told MailOnline they were shocked after the 'big bang' from the controlled explosion went off at Buckingham Palace.

While none saw the incident, many remarked they had heard a bang that sounded like a 'gunshot' as authorities detonated the suspected shotgun cartridges thrown over the fence.

Mary-Jane Willows, who has camped out at multiple royal events including the Diamond Jubilee, said: 'The police threw a cordon up and there was a bang.'

But she added that royal super fans wouldn't let the person responsible ruin their fun and he would be quickly forgotten when the event got closer.

'Let's rub him away and forget about him', she said.

One passerby remarked it was worrying, but the police had acted swiftly.

The person, who asked to remain anonymous, said: 'It's concerning that someone would do something like this. Why would you want to do that? Everyone's so excited about Saturday, it's a shame someone wants to ruin that.

'But the police seemed to have it under control, we didn't know anything had happened until the big explosion.'

A controlled explosion was heard on live TV as police investigate suspicious bag at Buckingham Palace. Jacog Rees-Mogg was presenting at the time

A general view of Buckingham Palace after a man was arrested and a subsequent controlled explosion was carried out

The scene near Buckingham Palace after a man was arrested after throwing items suspected to be shotgun cartridges into the grounds of the Palace

Buckingham Palace confirmed the King and Queen were not in residence when the incident occurred. But a Royal spokesperson would not answer whether any other relatives or family members were there when it unfolded 

An ambulance is pictured at Buckingham Palace after a man threw suspected shotgun cartridges into the palace grounds

Officers guard the gates outside the royal residence after a man was arrested on suspicion of possessing weapon

Met Police confirmed there were no reports of any shots fired, or any injuries to officers or members of the public.

'Officers remain at the scene and further inquiries are ongoing,' added Mr McDonald.

Police added that the objects were recovered, and that the man is now in custody after he was also found to be in possession of a 'suspicious bag'. 

'The man has been arrested on suspicion of possession of an offensive weapon and will be taken into custody.

'Cordons are in place after the man was also found to be in possession of a suspicious bag. Specialists are in attendance and will assess the item.'

MP Jacob Rees-Mogg was presenting from the palace for GB News while police carried out the controlled explosion. 

The politician told MailOnline that he arrived at Buckingham Palace around 7.20pm, after the man had already been arrested.

'It was all a bit odd,' Mr Rees-Mogg recalled. 'It wasn't closed off yet.'

The MP, who was evacuated as the incident unfolded, added: 'It wasn't much at all. We could've carried on broadcasting rather than evacuating.'

Mr Rees-Mogg said that despite the incident, he has no safety concerns for the upcoming Coronation festivities.

Police say they are not currently treating the incident as terror-related. It is understood it is being treated as an isolated mental health incident

Police are seen outside the palace gates after the incident

Officers had detained the man and taken him into custody. Cordons had been put in place after the man was found to have a suspicious bag

Police added that the objects were recovered, and that the man is now in custody after he was also found to be in possession of a 'suspicious bag'

Officers stand guard near Buckingham Palace after a man threw a number of items - suspected to be shotgun cartridges - into the palace grounds

Officers are pictured outside Buckingham Palace after a man approached the palace's gates in central London and threw a number of items

Noting how the suspect 'wasn't near the King,' Mr Rees-Mogg stated: 'An event with millions of people poses some element of risk. The question is getting the balance right.'

He said the 'key to this is not to overreact' and believes the risk posed with the Coronation is 'proportionate to scale of event'.

The arrest comes as police and security services prepare for King Charles' coronation on Saturday, which is expected to see large crowds line the streets of London and heads of state from around the world attend the formal coronation ceremony.

Royal fans were also starting to set up camp along The Mall to ensure front-row seats of the historic event this weekend. 

More than a dozen brave souls have set up tents and makeshift accommodation at the barriers days before thousands of people are expected to line the streets for the Coronation.

A jovial atmosphere has sprung up among the group, but this was punctured by the explosion.