The 12,000 poppy petals – representing the number of the city's dead in the 1914-18 conflict – were scattered on the river at the end of a remembrance service at Knight's Way Bridge, near the Royal Armouries museum.

It was organised by the city council in build-up to the unveiling of Leeds's wartime-themed entry in next week's Chelsea Flower Show.

Council staff laid on the ceremony after being moved by tales of bravery heard while researching the project.

The city's entry at Chelsea is a 1,800 sq ft garden inspired by the grounds of a house in Belgium which operated as a rest centre for British troops in the First World War.

Poppies were used during the poignant climax to yesterday's service because they are the flower of wartime remembrance.

The service was led by the Rector of Leeds, Canon Tony Bundock, and attended by the leader of the council, Coun Andrew Carter.

Representatives of the Leeds Pals, the Leeds Rifles and the Kings Own Yorkshire Light Infantry were also present. The 15-minute service included prayers and the sounding of Last Post by a bugler.

After the ceremony Coun Carter said: "It was extremely moving. It's only right that we take the time to reflect on the enormous sacrifices these young men made."

The flower show runs from next Tuesday to Saturday. The Royal British Legion is one of the Leeds entry's sponsors. For more details, visit www.leedsatchelsea.co.uk.