Dorset council are set to restore the Osmington white horse after a botched repair by Anneka Rice and a group of scouts 20 years ago degraded the famous site.

The 323ft high horse, cut out of the Dorset limestone for George III in 1808, who was a regular visitor to near-by Weymouth, has faded at various times in its history as the limestone doesn’t stay white for long.

Sarah Hardige, South Dorset Ridgeway Heritage Project Officer, said: “The TV show Challenge Anneka covered the horse in small limestone scalpings which in time have darkened and washed down the slope changing the shape of the horse.”

Rodney Legg, a Dorset historian and author, described the repair as: “A bit of a do-it-yourself garden landscaping.”

The Challenge Anneka programme, hugely popular in the eighties, enlisted a group of local scouts to aid Anneka in her challenge to whiten the horse.

Ms Rice told the Telegraph: “We didn’t just turn up and start work on it. I can only think we were given the wrong advice at the time. I love the white horse, as I drive past it regularly. I will be the first to volunteer to help restore it.”

Ms Rice’s meteoric rise from being a secretary at the BBC to national celebrity was only matched by her rapid exit from the spotlight when the programme was axed in 1995, culminating in Madame Tussaud’s melting down her effigy.

Steve Wallis, senior archaeologist for Dorset County Council, who is leading the restoration work, said: “We want to restore the white horse in all its glory. To do that they have to remove the stone chips, before undertaking a geological survey to determine the original shape of the horse.”

It’s believed the horse was based on George III’s favourite grey charger. Restoration funding is coming from the lottery and Natural England.