Ian Bell proved his form and fitness ahead of next week's Ashes squad announcement with a nerveless ton to see Warwickshire to a three-wicket victory over luckless Somerset in the CB40 final at Lord's.

Bell played the role of finisher with aplomb, scoring 107 in 95 balls as the Bears edged past a modest total of 199 - achieved thanks to leg-spinner Imran Tahir's five wickets for 41 runs - to take the season's final piece of silverware.

Bell is not involved in England's one-day series against Pakistan having just come back from a broken metatarsal - but he showed why he is considered an automatic pick for Australia with a classy innings.

For Somerset it was the third disappointment of a traumatic season which saw them lose the Friends Provident t20 final on the last delivery and ousted from the top of LV= County Championship in the dying seconds of the campaign on Thursday.

Somerset got the early wickets they needed to defend such a low target, Ben Phillips sending Neil Carter back for five and Alfonso Thomas bullying Keith Barker out for an uncomfortable three.

Jonathan Trott, released to play between one-day internationals, was watching at the other end and was joined by Bell at 20 for two.

Trott picked up four off a meaty inside edge but Bell started confidently, deflecting Mark Turner for four through cover and hoisting Phillips over the top on the charge.

Phillips was unfazed by the gesture and responded with a beauty that brushed Trott's edge on the way to the wicketkeeper, leaving him gone for 17.

Bell hit successive fours off Turner to calm the nerves but the west country side soon tightened up to slow the scoring rate.

Nevertheless, Bell forged past 50 from 53 deliveries as Warwickshire brought up their hundred.

Jim Troughton (30) batted within himself, one full-blooded drive off Turner aside, until Thomas had him caught at the wicket to end a 79-run partnership.

Darren Maddy added only nine before Turner made it 135 for five to bring new doubts, although new man Rikki Clarke belted the same bowler for the first six of the day, followed by a four.

With five overs remaining 36 were still needed and Clarke (19) perished attempting to clatter six of them off Peter Trego .

Bell was calmer, thrashing Turner for 20 in a decisive 38th over, exiting just before the winning runs were scored.

Somerset's innings consisted of three distinct parts, beginning with a bright opening partnership, moving on with a gritty fourth-wicket stand worth 95 and ending with a catastrophic collapse.

An opening pairing comprising England's past and present - Marcus Trescothick and Craig Kieswetter - were sent in by Warwickshire's stand-in captain Bell and they were not slow to attack.

Trescothick drilled Carter's fifth ball of the day through the covers for four, with his younger partner repeating the stroke on the up soon after.

Barker made the crucial breakthrough with the score on 41, cramping Trescothick (21) for room as he chipped to Chris Woakes at midwicket.

Trego (11) fell in similar fashion and Kieswetter joined him in the pavilion for 37 after thrashing Carter down Barker's throat at deep midwicket.

That brought Nick Compton and James Hildreth together for a stand that was high on energetic running but low in expansive strokeplay. Compton hit his first boundary off his 49th ball but scored consistently enough to make 60 in 65 deliveries.

Hildreth was marginally more attacking, managing three fours before being run out for 44 attempting an ill-conceived single.

Thereafter it was left to Tahir to dominate proceedings, a tidy first spell merely the appetiser for a second that yielded five for 14 in four overs.

Compton and Jos Buttler (nought) were both pinned leg before, Arul Suppiah (one) was bowled by a sharp leg-spinner, while Murali Kartik and Phillips were also undone by the former Pakistan A international.

In all the collapse saw seven wickets fall for 23 runs and tipped the momentum irrevocably in the Bears' favour.