Alex Hales smashed the highest score in a one-day final at Lord's as Nottinghamshire successfully hunted down a target of 298 to leave Surrey defeated at the last for the third successive year in the Royal London Cup. Hales' extraordinary innings of 187 not out accounted for 63% of his side's runs, eclipsing an accomplished, unbeaten 144 from Surrey's Mark Stoneman earlier in the day, as well as Geoffrey Boycott's previous mark of 146, made during the 1965 Gillette Cup final.

Boycott's innings for Yorkshire came in a 60-over innings, just two years after the advent of one-day county cricket. While he might bridle at the suggestion it should have been surpassed before now, Boycott would surely approve of his record being taken by a player of Hales' calibre in limited-overs cricket, a man already in possession of the highest ODI and T20 scores for his country.

"Incredible, one of the best days I've had in cricket," Hales said. "The game went from one side to the other, they were on top to start with, we fought back really well with the ball, they took wickets early on and then we fought back as well, so it's a great feeling to win the trophy."

As remarkable as the scale of Hales' contribution was the ease with which he - and Stoneman - batted on a surface that was never quite as true as it appeared. Chris Read's bustling 58 was the third-highest score in the match, as the Nottinghamshire captain, who retires at the end of the season, kept Hales company in a stand of 137 that lifted them from a troubled 150 for 5 to the brink of comparatively comfortable victory in the afternoon sunshine.

Hales finished with the highest List A score ever made at Lord's and the highest for Notts as the county claimed their second limited-overs title in four years. Read, who lifted YB40 trophy here in 2013, will play in an exhibition match at Lord's for MCC against Afghanistan next week but could not have wished for a better finish on his last visit with Notts.

Surrey's 297 for 9 was the most substantial score in a one-day final since Durham made 312 for 5 ten years ago, but the fact it did not feel out of reach was reflective of the new realities of the game in England. Having chased 371 to beat Essex in their semi-final - after scoring 429 for 9 at Taunton a few days earlier - Notts were unlikely to be intimidated. Only Warwickshire, who hauled in a target of 322 over the course of 60 overs in 1993, had successfully chased more in the final of a one-day cup.

Hales certainly wasn't backwards in coming forwards during a majestic innings of controlled aggression, replete with crunching drives and scything pulls. He was dropped on 9, a rasping shot off Sam Curran that burst through the hands of Ollie Pope at cover, but quickly progressed to a 35-ball fifty - by which time he had lost opening partner Michael Lumb and Riki Wessels lbw for single-figure scores - and then his century from 83.

He had amassed 82 out of Notts' first 100 and 144 out of 200 and was still contributing two-thirds of the total by the time Read provided a belated support act. Hales peppered the boundary with 20 fours and four sixes - no other batsman managed to clear the ropes - and when he raised his 150, from 120 balls, Surrey could sense the game had gone for the third year running. Such was the power of his mojo, had it come a week earlier, Hales might have ended the day headlining the Pyramid Stage at Glastonbury.

"I definitely wanted to attack the Powerplay, I thought they batted really well in it, looked like you got good value for decent cricket shots on a quick outfield," he said. "That was my plan, obviously losing a few wickets meant you had to alter that a little bit but the way Ready played - we had our backs against the wall, to come out and score at a run a ball, when they had their tails up in the field and with the ball was a great effort. So, a special win.

Told he had passed Boycott for the record in a final, he dissolved into giggles: "In a one-day game? That's surprising... I didn't know that but any chance you get to set a record is amazing."

While Hales motored smoothly, the throttle coughed and spluttered at the other end. Samit Patel, in such purple form going into the game, hooked Ravi Rampaul wastefully to fine leg before Jade Dernbach had Brendan Taylor caught behind. Hales just needed someone to hang around but Steven Mullaney, who had earlier delivered a pivotal spell of 9-0-50-2, became the fifth wicket to fall when Sam Curran won another lbw decision.

This was the first Royal London final to be played in July, although the slightly grey start to the day and a middling crowd initially made it seem much like the faded September showpiece of recent seasons. Despite a firm surface and a magnificent effort from Stoneman, who had to rein himself in as wickets fell around him, Surrey were still somehow undone by a combination of spin and medium-pace nibble in the fashion of so many sides batting first at Lord's on slow, late-summer pitches.

Stoneman, overlooked by England when the Test squad was announced in the morning, was like Hales given a life when, on 32, an uppish drive presented Mullaney with a simple catch in the covers, only for the ball to squirm free. Notts had already seen Jason Roy dropped off the first ball of the match, a shocker from Wessels at slip, and Surrey, having chosen to bat after Gareth Batty again won the toss, must have hoped their luck in Lord's finals had turned. Notts' fielding remained somewhat ragged throughout, though it was Pope who would have most cause to regret his lapse.

After an opening stand of 83 in 11 overs had given Surrey an excellent platform, Patel struck with his first delivery; Mullaney this time accepted the opportunity with alacrity, Roy getting a leading edge to cover as the ball gripped a little.

That brought in Kumar Sangakkara, author of two Royal London hundreds this season (plus six more in the Championship). "If Sanga doesn't come off, we're stuffed," opined one Surrey supporter on the way down Wellington Road before the game. Successive defeats in the final of this competition in 2015 and 2016 had clearly taken a psychological toll.

Sangakkara began with his usual coiled intensity, walking into crisp forward defensives and nurdling singles before striking his first shot in anger from his 25th ball - a stroll down to flay Stuart Broad over mid-off's outstretched arm for four. Two more boundaries followed in Broad's next over, flicked to fine leg and then glided to third man with watch-maker's precision, but then came the minor misjudgement that precipitated a major crisis for Surrey.

Mullaney, who played a part in each of the first five wickets to fall, claimed the one every county bowler wants this season when he induced a thin nick to the keeper. Sangakkara's 30 would turn out to be the second-highest contribution for Surrey, as they lost 4 for 39, Mullaney and Patel combining for an old-school knackering of a gleaming middle-order, full of young talent but unable to provide Stoneman with any substantial support. For Surrey, it was deja vu all over again.