Somerset 197 (Trescothick 52, Finn 4-41) and 147 for 7 (Trescothick 50, Murtagh 3-43) drew with Middlesex 283 (Malan 69, Gregory 5-58) and 132 for 6 dec.
An entertaining finish to a weather-ravaged match at Merchant Taylors' School saw Somerset, set 219 to win from 40 overs by Middlesex, make a spirited attempt before accepting the draw at 147 for 7.
Middlesex had earlier declared their second innings at 132 for 6, after just 29 overs' batting, in an effort to force a result following the loss of almost 144 overs to bad weather during the game.
Marcus Trescothick, leading Somerset from the front, played a captain's innings of 50 from 86 balls, to complete his second half-century of the match and he was supported well by Tom Abell, who made 21, James Hildreth's 29 and 23 from Jim Allenby as Middlesex were made to sweat more than a little. At 113 for 3, with 15 overs left, Somerset were preparing for a final assault on a tough target - but Middlesex held their nerve.
In the end, after Peter Trego had been superbly held at third slip by Sam Robson off seamer Tim Murtagh, who finished with 3 for 43, Middlesex had just three overs in which to take the last three Somerset wickets - and it proved beyond them. Hands were shaken after 39.4 overs had been bowled.
Toby Roland-Jones helped Murtagh to spearhead the Middlesex attack in the absence of Steven Finn, who missed the last day after being retained in England's second Ashes Test squad, and the tall paceman bowled with great heart and stamina to take 2 for 45 from 16 overs. James Harris, Finn's replacement, chipped in with the wickets of Jamie Overton and Allenby just when it seemed as if Somerset might even make a fist of reaching their tough target.
Overton, promoted from No. 11 to have a swing, skied a return catch from an attempted carve to leg to go for 5, and Allenby was brilliantly held by a sprawling Eoin Morgan at deep cover. Somerset had begun the last ten overs needing another 84, with six wickets in hand, but Allenby's fall signalled the end of their chase.
In Middlesex's second innings it was skipper James Franklin who led the charge with 32 from 25 balls in which he swung Tim Groenewald for two sixes in an over, and John Simpson, with 17 not out, also drove Lewis Gregory over long on for six. The declaration came immediately after Ollie Rayner, in to face one ball after Franklin had heaved to deep-midwicket, slammed a straight four back past bowler Gregory.
But batting was a tricky business on a pitch which was under cover all day yesterday when the third day was washed out, and for 25.3 overs on day two because of showers. There was more frustration this morning, too, when just 74 minutes' play was possible in the first session before light rain frustratingly arrived at 12.14pm to drive the players from the field. An early lunch was taken at 12.45pm but more rain and bad light meant play was unable to resume after lunch until 2.10pm. A further brief bad light stoppage, with Middlesex at 66 for 3, threatened to ruin the prospect of an interesting finish, but thankfully the skies above north-west London lightened again.
Somerset resumed their first innings on 185 for 8 this morning, in reply to Middlesex's 283 on day one, and added only 12 more runs in 4.3 overs before being all out for 197. Groenewald was superbly held by Nick Compton when he skied Murtagh to mid-off, from the tenth ball of the day, and Michael Bates was then brilliantly run out by Morgan at mid-on as he tried to pinch a single from the last ball of the 75th over.
When Middlesex batted again, Robson played some fine early shots before being caught behind off a beauty from Groenewald for 18, while Joe Burns was also beaten off the pitch by Trego's seam movement and held at second slip for 10 by Trescothick.
After lunch, Compton went skilfully to 30 before edging Overton to second slip, soon after the pacy Overton had detonated Dawid Malan's stumps for 16 with a searing yorker. Morgan completed an unhappy match with the bat when, after Overton had given him a brief working over, he steered Trego to third slip to depart for a nine-ball duck and a dreaded pair.