An animal rights activist who suggested waging bets on sick children has insisted the online comment “wasn’t a cruel joke”.

Campaigners angry over a children’s charity’s fundraising event at the greyhound stadium in Hove launched a drive to stop it happening.

Activist Jill Kirby emailed Rockinghorse and posted a comment on Facebook asking “if they are going to arrange a day at the hospital so we can go and bet on the children.”

The event was organised to raise £5,000 for a cardiac monitor for the Royal Alexandra Children’s Hospital – but was cancelled after “despicable” abuse.

Defending her comments Ms Kirby said: “I never mentioned dying babies, it was a remark about children racing round the ward which is completely different. It wasn’t a ‘cruel joke’.

“I have apologised to the charity via The Argus, I am in the process of writing an email to Rockinghorse to apologise.”

Describing his decision to cancel the event, Rockinghorse chief executive Ryan Heal told The Argus yesterday: “The abuse reached such despicable heights that I had to make this decision in order to protect the staff, our proud brand and the wonderful children and their families we support.

“I think the worst thing was the impact on families who have lost children. It is beyond the pale. What shocked us the most was how misplaced their anger seemed to be.”

Laura Slade, a supporter of the campaign group Greyt Exploitations, posted dozens of tweets and sent a series of emails to Mr Heal and other staff – but denied they amounted to a social media hate campaign.

She said: “My intention in contacting them was always to promote awareness of the nature of greyhound racing which I believe on the basis of facts to be a cruel industry.

“I used all available communication channels until I got finally a response.

“When I finally received an unpersonalised email from the CEO saying the event was cancelled, I was delighted, thanked him immediately and made a donation.”