Question: Who did on-field captain for  the NatWest t20 Blast most recently played for?

Context articles: List of English Twenty20 cricket champions
Warwickshire County Cricket Club in 2014
2014 English cricket season
Warwickshire County Cricket Club in 2015
2017 NatWest t20 Blast
Glamorgan County Cricket Club in 2014
2015 NatWest t20 Blast
Jim Allenby
2014 NatWest t20 Blast
2016 NatWest t20 Blast

The English Twenty20 cricket champions are the winners of the England and Wales Cricket Board (ECB) Twenty20 competition for first-class cricket counties, most recently the Friends Life t20, although from 2014 this has been replaced with the NatWest t20 Blast.
 The competition culminates with 'Finals Day': a single day on which both semi-finals and the final are contested at the same ground.
 Northamptonshire are the current champions, claiming their second title in the 2016 season.
The 2014 season was the 133rd year in the history of Warwickshire County Cricket Club and their 120th as a first-class county.
 In 2014, Warwickshire competed in the first division of the County Championship, Group B of the Royal London One-Day Cup and the North Division of the NatWest t20 Blast.
 In the NatWest t20 Blast, the club competed under the name "Birmingham Bears" for the first time.
 Twenty years after completing a treble, Warwickshire won their first ever t20 title, beating Lancashire in the final on home soil.
 They also reached the final in the Royal London One-Day Cup, where they lost to Durham at Lord's.
 Warwickshire also finished second in the County Championship, behind Yorkshire.
The 2014 English cricket season began on 1 April with a round of university matches, continued until the conclusion of a round of County Championship matches on 23 September.
 Three major domestic competitions were contested: the 2014 County Championship, the 2014 Royal London One-Day Cup and the 2014 NatWest t20 Blast.
 The Royal London One-Day Cup and the NatWest t20 Blast were newly created competitions as from the 2014 season, replacing the Clydesdale Bank 40 and the Friends Life t20.
The 2015 season is the 134th year in the history of Warwickshire County Cricket Club and their 121st as a first-class county.
 In 2015, Warwickshire are competing in the first division of the County Championship, Group B of the Royal London One-Day Cup and the North Division of the NatWest t20 Blast.
 In the NatWest t20 Blast, the club are competing under the name "Birmingham Bears" for the second time.
The 2017 NatWest T20 Blast is the current Twenty20 cricket league in England and Wales.
 It is the fourth season of in which the domestic T20 competition, run by the ECB, has been branded as the NatWest t20 Blast.
 The league consists of the 18 first-class county teams divided into two divisions of nine teams each with fixtures played between July and September.
 Ahead of the final round of fixtures, 15 teams were still in a position to qualify for the quarter-finals.
 The final is scheduled to take place at Edgbaston Cricket Ground in Birmingham on 2 September 2017.
 The teams competing in the finals will be Birmingham Bears, Glamorgan, Hampshire and Nottinghamshire Outlaws.
The 2014 season marked Glamorgan County Cricket Club's 127th year of existence and its 93rd as a first-class cricket county.
 In 2014, Glamorgan played in the Second Division of the County Championship, Group B of the 50-over Royal London One-Day Cup and the South Group of the NatWest t20 Blast.
 It was the first season in charge for head coach Toby Radford.
 The on-field captains were Mark Wallace for the County Championship and Royal London One-Day Cup, and Jim Allenby for the NatWest t20 Blast.
 Unlike other counties, Glamorgan competed in limited-overs cricket without a nickname for the second year in a row.
The 2015 NatWest t20 Blast was the second season of the NatWest t20 Blast, the English and Welsh Twenty20 cricket competition.
 The competition ran from 15 May 2015 to Finals Day at Edgbaston on 29 August.
 The competition was won for the first time by Lancashire Lightning, who defeated Northamptonshire Steelbacks in the final.
James "Jim" Allenby (born 12 September 1982 in Perth, Western Australia) is an Australian cricketer who most recently played for Somerset.
 He is a right-handed batsman and a right-arm medium-pace bowler.
The 2014 NatWest t20 Blast was the first season of the NatWest t20 Blast, the English Twenty20 cricket competition.
 The competition ran from 16 May 2014 until Finals Day at Edgbaston on 23 August, which was won by Birmingham Bears.
 The competition replaced the Friends Life t20 competition.
 With attendance figures over 700,000, it was the most attended season of T20 cricket in England since the format began in 2003.
The 2016 NatWest T20 Blast is the third season of the domestic T20 competition, run by the ECB, branded as the NatWest t20 Blast.
 The league consists of the 18 first-class county teams divided into two divisions of nine teams each with fixtures played between May and August.
 The final took place at Edgbaston Cricket Ground in Birmingham on 20 August 2016.