Huge security high alert at Buckingham Palace as Queen's coffin set to arrive in London

Buckingham Palace's security has been beefed up as Queen Elizabeth's  coffin is set to arrive in London on Tuesday.

Thousands of mourners have paid tributes to the Queen in Edinburgh as the Queen lies at rest in St Giles' Cathedral - and yet more are expected once her coffin arrives to London on Tuesday.

Experts think it's really a very challenging time for the law enforcers. The primary concern for the security services over the coming days is public order rather than a terrorist threat.

As per reports, the Metropolitan Police is leading on this, working closely with Police Scotland and the security service, MI5. They have rehearsed extensively for this week.

The current UK terror threat level remains at "substantial", meaning a terrorist attack is thought to be likely, but not highly likely or imminent - which would be two levels above where we are now, according to BBC.