Former Hampshire Constabulary chief inspector Philip Kedge attended the protests on Monday.
The protests have been ongoing for more than a week, seeing thousands of people flood to the capital.
Mr Kedge was with Hampshire Constabulary from 1990 to 2012, previously studying at the University of Portsmouth.
Speaking to The Guardian, he said: ‘I have a seed of doubt that’s been growing in terms of what’s been happening to our environment and I decided that I could do two things.
‘I can go sit on Bournemouth beach and enjoy the sunshine with ice cream or I can come here and find out more.
‘My respect to all the service officers here – I’ve seen nothing but the utmost professionalism and respect.
‘The same goes to the protesters who have treated the police with dignity and respect.’