Marcus Trescothick sent out a warning to both Pakistan and Australia with a sparkling century in his first innings of the summer.

The England left-hander, who has not played any competitive cricket since returning from Sri Lanka last month, completely dominated some rather tame Glamorgan bowling.

The 25-year-old's 172-ball century included 15 fours, most of which came from some glorious offside driving, and a six.

Trescothick dominated Somerset's opening stand with Piran Holloway, who reached 50 but off 161 balls.

And after easily reaching the follow-on figure of 204 the pair broke the record for the Somerset first wicket against Glamorgan of 210 set by Jimmy Cook and Peter Roebuck in 1990 on the same ground.

Glamorgan must have wondered when they were going to take their first wicket and when one eventually arrived it came in a bizarre fashion.

A Trescothick drive was deflected on to the stumps by Darren Thomas with Holloway out of his ground. It ended a 240-run partnership for the first wicket.

The dismissal must have affected Trescothick's concentration because he was out himself two balls later holing out to wide mid-on.

It ended a fine innings from the England man who had faced 226 balls in a four and a half hour vigil that included 23 sweetly struck fours and a six.

Skipper Jamie Cox took up the Somerset onslaught as the visitors finished the day on 307-3 after they lost Peter Bowler before the close.

Earlier in the day Glamorgan had declared their first innings on 353-9 after registering a fourth batting point. Richard Johnson ended with 5-106 - his second five-wicket haul of the season.

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