Jessica Harrington has criticised the "seriously annoying" level of extra paperwork involved in sending runners to Britain from Ireland in the aftermath of Brexit.
The Cheltenham Gold Cup-winning trainer has sent Grand National runner-up Magic Of Light over to compete in the Grade 2 Matchbook Betting Podcast Mares' Hurdle (1.15) at Ascot on Saturday.
Harrington, who will stay in Ireland rather than make the trip, says the new rules and regulations required for the transport of the mare have added €700 on top of the usual costs.
Last week Willie Mullins expressed concern over extra VAT charges on sending horses to Britain after Brexit, although his fears were eased as he sent Grangee to Market Rasen on Saturday without any extra charge being levied.
Speaking about the new process, Harrington told Sky Sports Racing: "We've got it organised, as far as I can tell. She is leaving here this afternoon and will be at Ascot at some point in the early morning.
"It's more the paperwork, that's the problem and what costs money. Before, we could just drive to the ferry, get on one end and off the other, and the only costs you had were the box, diesel and the lads you took.
"Now we have all this paperwork to do for the Department of Agriculture and vets to pay to get all these forms done. That's what is so seriously annoying.
"I knew this was going to happen because I know what it was like before we had the Tripartite Agreement and we were all in the EU."
Also staying at home is Magic Of Light's regular jockey Robbie Power with Jonjo O'Neill jnr set to take over in the saddle.
The ten-year-old won this race last year and is following a familiar route towards Aintree having also retraced her steps by winning the Listed Pertemps Mares' Chase at Newbury in December for the third year running.
However, Magic Of Light will face stiffer competition at Ascot this time in the shape of Dan Skelton's Cheltenham Festival heroine Roksana.
Harrington said: "She's in great form. She has gone exactly the same route as the last two years with the chase at Newbury and now the hurdle at Ascot.
"Her versatility has just been amazing. My only worry is if the ground is very heavy, but we're the second race so hopefully it shouldn't be too bad."