Under an agreement struck in 1418, farmers were allowed to move their livestock along a then-countryside route in exchange for a small fee.

Farmers continue to pay a token fee to the city council in tribute to the historic agreement - which stipulated a payment 50 mediaeval “maravedis” per 1,000 sheep - and assert their right to continue using the route, which now cuts through central Madrid.

The defiant sheep parade has taken place every year since 1994, but this year was the biggest yet, in celebration of the 600th anniversary, El Pais reports.