Horse racing 2026 flat season preview: Back Aiden O'Brien to dominate at Epsom again

The jumps season may be in full swing, but Races Now co-host Adam Smith (@Smido11) always has one eye on his beloved flat game.

In his latest Focus On The Flat column, Smido takes a closer look at what top-level British horses will be staying in training for 2026 and flags up two specials bets that have taken his eye.

Which top-tier flat horses will stay in training for 2026?

At this time of year, flat racing fans like me often wonder which older horses are staying in training for the season ahead.

Retirement announcements can often go under the radar when most eyes are on the jumps action. Given last year produced Group One winners at SPs of 33/1. 66/1. 150/1. 200/1 and 100/1, it’s no surprise that more of them are staying in training than usual.

As of 2025, there are 38 Group One races in the UK and by my reckoning, the winner of 30 of them will be returning to racing in 2026. There are minor question marks over the likes of Jan Brueghel and Lambourn, whom I assume are racing on but no official confirmation either way yet.

Plus, we can look forward to seeing the likes of two top level scorers Opera Singer who missed the whole of last year, and Notable Speech, who is still going as a five year old having won the Breeders Cup Turf Mile in November.

Then we have the very exciting Zeus Olympios, who is unbeaten in four and sure to be dining at the mile division’s top tables this year. A division that includes Field Of Gold, Opera Ballo, Notable Speech, possibly Opera Singer and perhaps Never So Brave.

How good would it be if Field Of Gold can get back to his electric best? That’s before we start talking about Guineas horses that might take on their older counterparts from August onwards.

The return of King Charles winner American Affair from injury could provide some clarity to a chaotic sprinting division which saw the seven sprint Group Ones in 2025 won by seven different horses, six of them remain in training.

Calandagan is without doubt the best horse in Europe and will be hanging round for as long as he fancies it, given he’s a gelding. Calandagan vs Ombudsman two or three times in 2026? Yes please.

Shout out to Merchant too, whom I was very high on last year before a combination of William Haggas’ safety-first approach and a minor injury curtailed his season at the end of July. I would consider a fit and firing Merchant as a contender in any and all mile and a half races from the Arc downwards.

O'Brien special markets make appeal

As usual in this column, thoughts return to the British Classics and this is the time of year where specials are available.

Bet365 offer 6/1 that Aidan O’Brien wins the Oaks and the Derby at Epsom. I think that’s a stonking bet for a variety of reasons.

Of the combined last 20 renewals of the two Classics, O’Brien has won 12 of them – six of each. Not only that, he also trained the favourite in three of those four Derbys he didn’t win in that period and furthermore was responsible for 32% of all Oaks and 27% of all Derby runners in the last 10 years.

Did I mention O’Brien currently has the top two in the Oaks betting and eight of the top nine in the Derby ante post lists? Also adding into the mix that the same supplier are 20/1 about O’Brien training the winner of all three Epsom Group Ones – Oaks, Coronation Cup and Derby. This should also be bet.

O’Brien has won seven of the last 16 Coronation Cups and fielded 22% of all runners over that time. Plus, Coolmore are sponsoring a cash-injected Coronation Cup for the first time in 2026 and have the perfect horse in last year’s Oaks winner Minnie Hauk to win it. Here’s hoping Calandagan, beaten in the Coronation Cup at 8/13 last year, starts his 2026 campaign elsewhere.

We pride ourselves on transparent P&Ls at Races Now but these bets won’t be included in it, given prices are only available with one supplier in a pretty niche market. Although I did back them to a fair stake on December 30th and the prices are still available at time of publishing.

Hopefully, if you are on a similar line of thinking to me, you can get on too.

Smido's Flat season 2026 ante post Specials betting fancies

Aiden O'Brien to train the winner of the 2026 Epsom Oaks and Epsom Derby - 6/1 (Bet365)

Aiden O'Brien to train the winner of the 2026 Epsom Oaks, Epsom Deby and Coronation Cup - 20/1 (Bet365)

Prices correct as of Tuesday January 6th 2026

*Due to these selections coming from specials markets offered by a single supplier, we will not include them in our overall seasonal P/L figures for the balance of fairness.*