Enough cricket followers will have passed wistful remarks to Marcus Trescothick about his non-availability against Australia for the issue not to be laboured here.

Suffice to say that, in county cricket, he remains the nonpareil, having scored more championship runs than any other first division batsman this season. Another century, surprisingly only the 33rd of his career, was compiled with clinical certainty.

In a different age, with no central contracts, Trescothick, 34, might have scored double that number. All the trademark shots were there yesterday as he strove to ensure that Somerset would not follow on in the face of a Yorkshire total of 438: the leg glance; the ball running fine of the wicket; the clip off the legs; the drive to the cover-point boundary; and the easy lofted six off the spinner, in this instance Azeem Rafiq.

Somerset's innings had stuttered when Arul Suppiah was caught at second slip and Justin Langer was leg-before to Steven Patterson. James Hildreth played the shot of the day in on-driving James Lee for four and had made fifty off 37 balls when he attempted to pick up the same bowler over square leg and was bowled. Craig Kieswetter, Peter Trego and Alfonso Thomas all went cheaply, but Trescothick remained.

He reached his century, his third of the season, by clipping Lee through mid-wicket for four, his nineteenth, as well as that six, which landed like so many before it, at the foot of the Old Pavilion. It was a weary batsman, this being another extremely humid day, who offered a return catch to Lee four runs short of 150, having faced 223 balls and struck a further five fours.

Yorkshire: First Innings
J A Rudolph b Stiff 191
J J Sayers b Thomas 8
*A McGrath c Kieswetter b Trego 40
A Lyth c Hildreth b De Bruyn 36
A W Gale c Trescothick b Willoughby 17
†J M Bairstow c Kieswetter b Thomas 39
A Rafiq c Kieswetter b Thomas 4
A Shahzad not out 27
M J Hoggard c Thomas b Stiff 26
S A Patterson c Kieswetter b Stiff 8
J E Lee c Trescothick b Stiff 2
Extras (b 13, lb 11, w 8, nb 8) 40
Total (112 overs) 438
Fall of wickets: 1-24, 2-104, 3-222, 4-267, 5-338, 6-370, 7-375, 8-409, 9-436.
Bowling: Willoughby 23-3-78-1; Thomas 24-3-65-3; Caddick 20-2-94-0; Stiff 19-2-92-4; Trego 13-4-30-1; Suppiah 8-4-28-0; De Bruyn 5-1-27-1.

Somerset: First Innings
M E Trescothick c and b Lee 146
A V Suppiah c Sayers b Hoggard 17
*J L Langer lbw b Patterson 4
J C Hildreth b Shahzad 51
Z de Bruyn c Gale b Lee 31
†C Kieswetter b Shahzad 28
P D Trego lbw b Hoggard 7
A C Thomas c Bairstow b Hoggard 13
D A Stiff not out 6
A R Caddick b Hoggard 1
C M Willoughby not out 6
Extras (lb 15, w 1) 16
Total (9 wkts, 78 overs) 326
Fall of wickets: 1-51, 2-64, 3-144, 4-215, 5-277, 6-287, 7-313, 8-315, 9-316.
Bowling: Hoggard 19-2-82-4; Shahzad 19-2-57-2; Patterson 14-2-55-1; Lee 13-1-63-2; Rafiq 13-0-54-0.
Umpires: T E Jesty and D J Millns.