An as yet unidentified man is seen on the roof of the Houses of Parliament and emergency services are called to Westminster Palace in London March 7, 2015.[Photo/IC]

LONDON - British police have detained a man who spent the night on the roof of the Palace of Westminster on suspicion of criminal damage and trespassing.

Scotland Yard said Sunday it was too early to know why the 23-year-old made his way to the top of Neo-Gothic masterpiece that serves as the seat of Parliament in Britain.

The man, wearing a grey top and black trousers, was pacing up and down between buttresses on the edge of the roof.

The roof of the palace along the River Thames has long served as favored location for stunts by campaigners, such as those opposing the construction of another runway at Heathrow.

Emergency services spotted the man just after 9 pm Saturday and he was detained early Sunday.