Campaigners hope residents will help form the letters of the word NO to send a giant 'human' message.

The stunt is part of a last push from the Save Hemel Hospital campaign to try and reverse decisions made about the town's health services.

The rally will feature guest speakers and live music at the Marlowes band stand from 11am before The Big No at 2.30pm, where hundreds of campaigners will stand in line to form the word NO.

A giant postbox will be set up for people to post letters to prime minister Gordon Brown.

Campaigners hope residents will write down their concerns about the hospital situation, or even simply ask for it not to close.

MP for Hemel Hempstead Mike Penning will then take the batch of letters to Downing Street.

The day will finish with a duck race on the river at the Riverside Shopping Centre to help raise cash to fund the rally.

Anyone can join in by paying for a duck on the day.

The protest was planned to take place in Gadebridge Park, but weather conditions have seen it move to the pedestrianised area of Marlowes in Hemel Hempstead town centre.

11.00 Welcome and introduction at Marlowes bandstand.

11.15 Music; funfair rides; letter writing and posting; buy your duck for the duck race.

12.30 Live music.

13.00 Speeches.

13.15 Live music.

13.45 Speeches.

14.00 Live music.

14.30 Walk to the Civic Centre.

14.45 The Big No.

14.50 Protest march to Riverside Shopping Centre.

15.00 The Great Gade Duck Race at Riverside.