The 1,585cc Dyna Super Glide was given to the Pope last June as a gift from Harley-Davidson to mark the company's 110th anniversary.

The Pontiff later donated the motorbike to the charity Caritas Roma, which works on behalf of the Catholic Church to support people in need.

The sale of the bike will raise funds for the charity to renovate a hostel and soup kitchen in Rome.

The motorbike is expected to fetch between €12,000 and €15,000.

The unique Harley-Davidson has the Pope's signature "Francis" signed on its petrol tank.

Ben Walker, the head of motorcycles at Bonhams auction house, said: "We are incredibly honoured to be selling this item on behalf of Caritas Roma.

"We hope to be able to do both Pope Francis and Harley-Davidson proud by raising a significant amount of money for a very worthy cause."