After the second of two Safety Car periods, Young took the lead from James Colburn and then set three fastest laps in a row to build a handy advantage over those behind.
From tenth on the grid, Coates knew he had to beat Young to be sure of the title. In wet conditions he made it as high as second in the closing stages but by then Young was too far ahead to be caught.
Young, who turned 18 on Friday, becomes the youngest Champion in UK Clio Cup history in this, the championship’s final season.
After one of the closest title fights seen in the championship’s 20 illustrious years, he and Coates end the season on seven wins apiece. Young’s winning margin over Coates in the end was just five points – 362 vs 357 (CLICK HERE for final points table).
Young has also delivered a first UK Clio Cup title for the MRM team with which he lifted the Clio Cup Junior crown in 2017.
He has also won the Graduates Cup for younger drivers. Coates’ Team HARD outfit though has won the Entrants Trophy for teams.
An elated Young commented: “It’s just unreal – Max and I have both given everything this season and it’s been nip and tuck all the way and sometimes a little too close for comfort. But to win this title is something else.
“Those final laps – when I got the lead it was head down and building a gap in case Max came through and he did. The last lap… I’ve never know butterflies like it. Coming out of the last corner I could see the team on the pit wall and the feeling I had going past them was just indescribable.”
A gutted Coates from North Yorkshire said: “I put everything into that race and not many people come through from P10 to P2… still after four years of trying it’s not come our way. We gave it everything and it’s been such a rollercoaster season with some massive highs and lows along the way.
“Congratulations to Jack. We’ve had our fair share of moments but he’s also driven well as in this race when the pressure was on. We might not always see eye to eye but we do respect one another.”
Behind Young and Coates on the podium, Westbourne Motorsport’s Colburn took third. MRM with InterCleanse’s Nathan Edwards and Westbourne’s Anton Spires were fourth and fifth. Saturday race winner, MRM’s Brett Lidsey, completed the top six.
The first Safety Car period was triggered when Colburn’s younger brother Ben crashed heavily on the opening lap in a tangle with another competitor. As soon as the race re-started the Safety Car was scrambled again when Ethan Hammerton’s Team HARD car became stranded in a gravel trap after a clash with Specialized Motorsport’s Luke Warr.
Result (provisional), Round 18, Brands Hatch GP:
1. Jack Young (MRM), 15 laps in 31m25.250s (65.05mph)
2. Max Coates (Team HARD), +2.800s
3. James Colburn (Westbourne Motorsport), +4.379s
4. Nathan Edwards (MRM with InterCleanse), +4.607s
5. Anton Spires (Westbourne Motorsport), +5.918s
6. Brett Lidsey (MRM), +7.913s
7. Jamie Bond (Team HARD), +8.044s
8. Jade Edwards (Assetto Motorsport with MRM) +13.991s
9. Finlay Robinson (Westbourne Motorsport), +14.463s
10. Luke Warr (Specialized Motorsport), +32.860s
DNF. Aaron Thompson (Westbourne Motorsport), +1 lap
DNF. Tyler Lidsey (MRM), +4 laps
DNF. Ethan Hammerton (Team HARD), +5 laps
DNF. Ben Colburn (Westbourne Motorsport), +14 laps
Fastest lap: Young, 1m50.348s (79.38mph)
CLICK HERE for full race result and data (leader board, sector analysis, speed trap figures etc).