At lunch Walker was told by his team-mates that the record was 277. "When the captain [Trevor Ward] called us in with me on 275 I thought it was a bit harsh. It wasn't until the Tannoy announcement that I knew I had done it after all."
The former England Under-19 captain, now 22, cuts a chunky figure at 5ft 6in with plenty of natural padding, so what he looked like before he shed the stone as he was ordered to do earlier this season, heaven alone knows. But having reshaped himself and the record books, he looks to have refashioned his career. The bare facts of his undefeated innings make impressive reading as an example of concentration and a degree of maturity so far lacking in Walker's make-up: 41 fours off 439 balls and only two false shots, towards the end of play on the first day.
His nine-and-a-half hour epic, apart from being the highest individual score by a Kent batsman against Somerset - Woolley, again, set the previous mark at 215 - also helped Kent reach their highest total on the ground against anyone.
More importantly, it helped put Kent into a commanding position against a lacklustre Somerset and reinforced their championship challenge. Needing 467 just to avoid the follow-on, things looked bleak for Somerset in the late evening sunshine as they lost three wickets, all of them to Dean Headley.
If there was a tinge of sadness that yet another piece of history has been overtaken, Walker, who now holds fourth place in the list of Kent's individual top scorers and also becomes the highest-scoring left-handed batsman in the county's history, at least promises to make viewing exciting. The misery of the last 18 months or so, when nothing seemed to go right for Walker, have been put behind him.
"I saw myself on video and my technique was terrible and perhaps I was too aggressive at times," he said. "But I sat down with the coach and sorted things out, got my head together and prepared myself to bat for a long time. I'm pleased to have stayed in so long for this innings."