Investec Oaks second Shirocco Star set out to make all under Darryll Holland, getting a few on the stretch turning in after a canny ride, but Smullen was happy to work his way into contention and Princess Highway could be spotted travelling well from some way out.

Shirocco Star just started to toil at the top of the straight as Smullen cruised down the outside and swept into the lead with two furlongs to run.

The 17-2 chance quickly pulled clear and did not stop, passing the post with six lengths to spare over 5-2 favourite The Fugue, who kept on to steal second place on the line.

The game Shirocco Star was a further short head back in third, but the Queen’s Momentary never got in a blow under Hayley Turner.

A clue to Princess Highway's chance was lurking in the form book, as she had Epsom heroine Was back in third when winning at Naas last time out.

Weld said: “It’s nice to come back and win the same race we won a number of years ago with her dam.

“She’s been a backward filly but progressed well during the spring and she beat the winner of the Epsom Oaks (Was) convincingly last time out.

“I thought this was an excellent renewal of the Ribblesdale, so we really had to improve to win today, and she’s gone and done it.

“Ascot has always been very lucky for me and she is a late developing filly.

“I thought Epsom might come a bit too soon for her and we gave her a little bit more time to come here today and go on for the Irish Oaks.

“My only concern was that the ground had maybe gone a bit slow for her, but they went a very true pace and Pat very wisely took his time on her and rode a brilliant race as always.”

Smullen said: ``She's a beautiful mare to ride. She's uncomplicated, travels and quickens.

“Our only fear was that the ground had gone too soft for her, but she handled it extremely well and it’s actually not too bad. I think she’d prefer better ground.

“She beat the Oaks winner quite well at Naas, so the form was there.

“I fancied her strongly today. I think she’s an extremely good filly. She stays a mile and a half and she quickens, so she has it all.”

The Fugue’s trainer, John Gosden, said: “The winner is very smart and we were beaten fair and square, but I’m disappointed it rained because my filly is much better on good to firm ground.

“We’ll freshen her up for the Yorkshire Oaks.”

Hughie Morrison said of Shirocco Star: “We all had hard races in the Oaks, but she kept going and it was a brave performance.

“She’s obviously one of the best fillies and the Irish Oaks in four weeks’ time would be the plan.”