Our panel of industry experts debate the biggest issues from 2017

Galileo is still going strong but he turns 20 in 2018. Who do you think is his most likely heir?

Cathal Beale, Irish National Stud CEO: I'll take two against the field with Gleneagles and his three-parts brother Decorated Knight. I thought the Gleneagles foals were high-quality animals. They both hail from the best pedigree in the book, containing multiple Group 1 winners at two, three and beyond. There are also two very successful sires in the immediate family in Giant's Causeway and the underrated Freud.

Jeremy Brummitt, bloodstock agent: It will be a long time before we see such a dominant stallion because the best prospects will be more evenly spread. Devotees of genotypes may find it hard to find another TT stallion to use, and in this day and age stallions who compile a first-crop record on a par with Galileo are likely to be rejected in their fifth covering season.

Karl Burke, trainer: Galileo will be an impossible act to follow. On paper they don't come any better bred than Australia, he was a great racehorse and on top of that his first crop looked very good.