According to The Crown Chronicles:
A new set of bollards have been placed outside of Buckingham Palace overnight, in response to the recent Westminster attack.
The yellow structures will prevent any vehicles mounting the pavement area – as happened in the attack on Wednesday – but will slow the flow of foot traffic at the tourist hotspot.
Security in the capital has been improved – London forces are thought to be operating at near double strength – and in other large cities, more police patrols have been noticed. Armoured bomb-proof vehicles have been spotted outside the Palace of Westminster; they can reportedly withstand an onslaught…