By Martin Robinson PUBLISHED: 02:54 EST, 14 April 2012 | UPDATED: 05:04 EST, 14 April 2012 Bookies are running scared today as they face a £10 million hit if a woman wins the Grand National for the first time today. Millions are set to watch sisters-in-law Katie Walsh, 27, and Nina Carberry, also 27, set their family loyalty aside and battle for racing's biggest prize at Aintree. The highly-rated pair, who were bridesmaid and bride two months ago, are both from two racing dynasties and have rode winners at Cheltenham but no woman has ever gone that step further and won the world's greatest steeplechase.
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Katie Walsh, 27, is on Seabass and Nina Carberry, also 27, will ride Organisedconfusion this afternoon
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If either makes history the bookies are set to be hit for £10 million
'If you’re not in, you can’t win, and hopefully he takes to the jumps,' Carberry added about her horse @placeholder yesterday.