Doctor Who: 13 Cool Details In David Tennant & John Barrowman's Last Of The Time Lords Commentary
11. Tennant Was Jealous Of John Simm's Laser Screwdriver
When comparing all the sonic screwdrivers of the NuWho era, David Tennant's is definitely a bit more compact than the likes of Matt Smith's and Peter Capaldi's.
In The Day Of The Doctor, the Tenth Doctor even points out how large the Eleventh Doctor's sonic really is, and he seems a bit miffed that his weapon is on the shorter side.
Funnily enough, this "screwdriver envy" isn't just felt by the character - it's actually felt by Tennant too.
During the commentary, the actor mentions that he's quite jealous of the size of the Master's laser screwdriver, which the Doctor attempts to use early in the episode.
In addition, Tennant jokingly adds that his own screwdriver is starting to fall to bits by this point in the season, presumably due to overuse.
To that, we say... buy a carry case to keep it in.