The number of hopeful competitor robots far outnumbered the available slots in every series of Robot Wars (with the exception of Series 1). All unseeded competitors were required to undergo a screening process known as the Qualifiers (or, initially, the auditions), in order for them to appear on the televised show. The robots would perform in front of the Robot Wars staff, giving demonstrations of control and mobility for entry into Series 2 and 3, and battling against other hopefuls from Series 4 to Series 7.
For Series 2 and 3, the auditions primarily consisted of weigh-ins, technical checks, photography sessions and an obstacle course referred to as the 'driving test'. The 'driving test' involved prospective robots negotiating through certain obstacles or accomplish various challenges similar to those encountered in the Gauntlet and Trial stages. These included knocking a football into a goal, driving over a see-saw, driving around or into some breeze blocks/barrels, driving in a figure-of-eight around some large springs and finally driving onto a piece of wood and spinning on the spot. Obstacles and challenges used for the 'driving test' varied in between each of the two series. In the Series 3 auditions, some competitors were also allowed to perform weapon tests in front of Robot Wars personnel, notably Hypno-Disc and Toe Cutter.
For Series 4-7, the qualifiers assumed the form of one-on-one or melee battles between two or more prospective competitors. They would take place in a modified or partially-finished version of the Robot Wars Arena, depending on which series they took place in. The arena for the qualifiers usually featured the paint scheme used by its televised counterpart, although it did not always feature House Robots and/or functioning hazards. Because of the arena's reduced safety capacity, roboteers were told not to flip their opponents out of the arena during their qualifier battles. The roboteers would be able to enter the qualifiers with more than one robot, but would only be able to qualify with one robot, this in particular affecting Team Mouse in Series 6 and 7. However, both Team Vader and Team Ming were able to enter Series 7 with two robots each.
The qualifiers always used the otherwise little-seen House Robot Shove as a cleaner/sweeper, as well as to push any immobilised/damaged robots to the arena entry gates if they could not be driven out on their own. Shove was used because it was more compact and easier to transport than Refbot.
For Series 8-10, no qualifiers took place. The qualification process for this series took the form of the producers reviewing applications sent in by potential entrants, and selecting them to compete. A number of robots that were not selected did eventually take part in an untelevised pilot episode, which was held and filmed with a live studio audience to test the camera equipment ahead of the main series. As in the original series, a number of reserve robots were also allocated for Series 8-10, even those which were initially not selected to compete; a notable example being Series 8 third-place finisher TR2.
As so few teams entered Series 1, no qualifiers or auditions were held for that series. In fact, there was actually a shortage of robots that were able to fight in the first series, as several robots suffered breakdowns etc. leading up to and during filming. As a result, three Stock Robots: Eubank the Mouse, W.Y.S.I.W.Y.G. and Grunt were used to make up the numbers.
Enough teams tried entering Series 2 to make having the auditions worthwhile. The auditions in this series featured an obstacle course, combining elements of the Gauntlet and Trial stages which successful applicants would have to face in the main competition.
Series 2 also saw the first occurrences of initially-rejected competitors being selected as reserves, occasionally replacing robots which were originally selected to compete, but were unable to for various reasons. Panda Monium, Wheelosaurus and Griffon were brought in to replace Cassius, Minotaur and Reckless Endangerment respectively. However, Cassius was able to participate in a later heat, while Minotaur and Reckless Endangerment were entered into the Super Heavyweight Championship, broadcast at the end of the series.
To allow some of the robots which were not selected a chance to compete in the televised show, a Reserve Rumble was held at the end of the series in the Grudge Matches special. The aforementioned battle was a one-off melee between five robots which were not selected for various reasons. Despite this, there were still some robots, like Team Power's Gnasher, which were not selected to compete and did not appear on the televised show at all.
Series 3 saw a considerable leap in the number of robots applying to participate, as 600 robots came to apply to feature on the televised show. It was not decided at the time of auditions that Series 3 would have no Gauntlet and Trial stages, so a Gauntlet-style obstacle course was still used to assess potential competitors. As more robots were applying, the judging was much more strict than it was in the previous series. For example, some robots, such as the original Major Tom, completed the course, but were still refused entry into the televised show.
Series 3 saw more reserve robots appearing in the main competition outright, with Binky, Flipper and Steg-O-Saw-Us replacing Daisy, The Parthian Shot and T-Wrecks respectively. Nevertheless, there were still many reserves, notably Wolverine, which would ultimately go unused.
A few robots which were not selected to compete in the main competition would still appear in the televised Series 3, competing in some of the side competitions such as Robotic Soccer and Pinball. Some of these, such as Six Pac and Dominator, would prove especially competitive in these side events. However, some robots which successfully entered the main competition, such as Evil Weevil, Razer and Killerhurtz, also competed in Robotic Soccer and Pinball, ostensibly to compare non-selected robots to robots which had been chosen for the main series.
The Series 3 auditions were held at the end of May 1999, over five months before the Series was filmed.
A record-breaking "Over 1000" teams applied for this series. Because the format of the show had changed to combat-only, the qualifiers now consisted solely of head-to-head battles between hopeful competitors, which gave the possibility of draws being declared in the event that there was no clear winner. Some robots were able to fight more than one battle. All thirty-two of the seeded robots for this series qualified automatically.
The Series 4 qualifiers were held as a live event, the first large-scale one of its kind, called Robot Mayhem. The event went on for two weeks, with six battles per day. Unlike in later series, the House Robots and some of the arena hazards - including the Pit and flame hazards - would be used in the qualifiers themselves. As well as the qualifier battles, the House Robots and some seeded robots, such as Razer and Hypno-Disc, would give demonstrations in the arena.
Due to some of these battles being decidedly "boring", even robots that won their qualifier battles were refused entry into the televised show, such as Dantomkia 1.0. Conversely, robots which lost their qualifier battles, like Warhog, were given discretionary places into the main competition, as they put on more entertaining performances.
V-Max, which originally failed to qualify, was selected as a reserve, and replaced Onslaught after it withdrew from the main competition at the last minute. There were other reserves for the Fourth Wars, notably Charybdis, that were not used.
Unlike Series 3, no robot that failed to qualify participated in the side events that were held during the filming of the main competition.
Series 4 also saw the first instance since Series 1 of a robot being able to qualify without having to go through the qualifiers. Scorpion was granted automatic entry, as the Robot Wars producers decided that it would look appealing in the arena.
The Series 5 qualifiers were also done in front of a live audience to promote the upcoming series. Unlike the Series 4 qualifiers, the live events for the Series 5 qualifiers were held at various locations as a live tour, at places including Glasgow, Cardiff, London and Newcastle. This time, Craig Charles was used as MC, whilst the House Robots and Pit were both used again for the qualifiers. Most of the battles were still head-to-heads, although melees were often used to quicken the judging and selection process.
At the time of the qualifiers, the top 16 seeds had been decided, but as the number of seeds was reduced from 32 to 24, the remaining eight seeds were decided during the qualifiers. Like the previous year, seeded robots such as Razer and Chaos 2 still attended the qualifiers as static displays and to give demonstrations to the audience.
Winning a battle still did not guarantee a robot's place in the main competition. Robots such as Cataclysmic Variabot and Barbaric Response failed to qualify despite winning their battles. Conversely, some robots that lost their battles, such as Kat 3, were awarded discretionary places.
Some robots, such as Spirit of Knightmare and Arnold A. Terminegger, despite failing to qualify for the Fifth Wars, would still enter competitions in the first series of Robot Wars Extreme, which was filmed at the same time as Series 5.
At many of the qualifiers, robots were put into groups of four. There would be two one-on-one first round battles, and the winners would then fight each other, the winner automatically qualifying for Series 5. For example, S3 and Dynachrome fought two other robots each before facing off against each other; S3 won the battle and automatically qualified.
For Series 6, the qualifiers were mostly four-way melees, like the first-round battles in the televised show, however some consisted of only two or three robots depending on availability. Unlike past series, each robot was strictly limited to one qualifier battle, and the winners would be guaranteed qualification. However, losers could still be awarded discretionary places.
Unlike Series 5, all of the Series 6 qualifiers were held at RAF Newton, with the arena closely resembling the form it took in the televised series. No active hazards or House Robots were featured in any of the qualifier battles, a practice which was to be repeated in Series 7.
Notably, future series champions Typhoon 2 would fail to qualify for this series, after losing its qualifier battle.
8645T 2 was disqualified from the qualifiers after its axe damaged the arena floor.
Some robots, such as Lightning, Cerberus and Typhoon 2, despite failing to qualify for Series 6, would still fight in competitions in the second series of Extreme, filmed a few months later that same year. In particular, robots such as Mad Dog, Chip and Pressure got their first chance to appear on the show in the New Blood Championship, broadcast as part of the latter.
In Series 7, the qualifiers were the same format as those of Series 6 - up to four-way melees with qualification guaranteed to the winner(s), and others being granted discretionary places. Around 200 robots attempted to qualify for this series.
For the first time in the UK championship, teams from outside the UK attempted to qualify. Twenty-two roboteers from eastern and central Europe pooled their money for transportation to the qualifiers. Arthur Chilcott of Random Violence Technologies even allowed them to use his backyard as a camp-ground. Of the teams that failed to qualify, some of those would still fight for the right to enter in the Third World Championships, held at the end of the series.
For the second consecutive series, Typhoon 2 lost its qualifier battle, this time to Ewe 2, losing alongside Big Nipper and Araknia. However, it, Big Nipper and Araknia were all given discretionary places for the Seventh Wars, with Typhoon 2 eventually going on to win the series.
Once again, Team Mouse were forced to only qualify with one robot, this time opting for Velocirippa, but Mighty Mouse was still listed as a reserve due to the team living nearby to the studio and being able to make it to filming in a short amount of time.
Despite the rule of only entering one robot per team, Team Ming was able to enter the Seventh Wars with Ming Dienasty and Zorro. Vader and IG-88, the two robots built by Team Vader, both entered the Seventh Wars because they were entered as separate teams.
- "...I entered Vader seperately to Paul Rose who entered IG-88. Whilst I was involved in assisting with the build of IG-88, I never appeared with the machine or was listed on the entry forms. My entry of Vader was a fairly late decision as I was at a loose end and the machine was just sitting in the garage, and then surprisingly during the qualifying "auditions" it was unbelievably dominant in it's heat."
- — Simon Latham on Facebook
There were some occurrences during the Seventh Wars where reserves could/should have been brought in, but were not. Terrorhurtz was disqualified from its heat due to a behind-the-scenes technicality, while Thunderpants was red-carded by Refbot after it was unable to leave its entry gate just before its first round battle. In both cases, no reserves were allocated to take their places, and the first-round battles they were scheduled to fight in began without them. Tanto had been considered as a reserve, but for unknown reasons was not brought in to fight when Thunderpants broke down.
- ↑ http://robotwars101.org/heavys/morepanda/construction5.html
- ↑ https://web.archive.org/web/20010518150324/http://www.tinweb.com:80/discus/messages/350/1655.html?FridayAugust2719990143am
- ↑ http://www.hypno-disc.co.uk/audition.htm
- ↑ 
- The Robot Wars Wiki's list of known qualifier battles that took place from Series 4-7 can be found here.
- The wiki's list of known robots that failed to qualify or were not selected for each series can be found here.
- Video of The Stag vs Gyrobot vs Scrap Dragon vs Shell Shock (Series 6)
- Video of Gyrobot vs Terror Turtle vs Fluffy (Series 7)
- Video of M2 vs King B Powerworks vs Pressure vs Thunderpants (Series 7)
- Video of Gravity vs Mechaniac vs RCC 2 (Series 7)