Manchester United are among the biggest clubs in the world and arguably one of the most successful over the past 30 years. Particularly during the tenure of Sir Alex Ferguson, the club became famed for stringing together various successful squads that brought several trophies to Old Trafford.Ferguson was an expert at securing brilliant signings, with him making some of the most successful transfers of all time. The likes of Roy Keane, Wayne Rooney, Rio Ferdinand, Nemanja Vidic and Cristiano Ronaldo have earned tremendous success at Old Trafford.Manchester United have also made some bizarre signingsSigning good players who turn out to be bad transfers is a common theme and can happen to any club. But signing players who do not even possess the quality to play at such a high level is a bigger blunder.United had the likes of Angel Di Maria, Memphis Depay and Radamel Falcao who were good players but could not perform at Old Trafford. But the Red Devils also made some signings who did not even deserve to don the red jersey in the first place.Here we take a look at five such players who did not deserve to play for Manchester United:#5 David BellionDavid Bellion of Manchester UnitedDavid Bellion was arguably Sunderland's best player the year before he moved to Manchester United. However, this was for a Sunderland team that had picked up one point after the halfway point of the season.Bellion had scored only one goal at the Stadium of Light before Manchester United bizarrely came calling in for the Frenchman in 2003. Although Bellion had technically left on a free transfer, the Black Cats lodged a complaint that they were owed compensation for the player. In the end an out of court settlement of £2 million was struck between the two sides.However, Bellion was never able to fully establish himself in Manchester United's star-studded team. After just eight goals in 40 appearances, the forward was shipped out on loan to West Ham. He later returned to his native country of France, initially joining Nice on loan before making a permanent move the following summer.Bellion had a decent time in France, even winning the French league with Bordeaux in 2008-09. But the forward never possessed the quality to don the red jersey in Manchester and is definitely one of the worst signings made by the Red Devils.Mirror Football@MirrorFootballManchester United flop David Bellion has a new job. Which is probably for the best... mirr.im/1ENDujd http://t.co/Lqn12dKwny4:04 AM · May 3, 201566Manchester United flop David Bellion has a new job. Which is probably for the best... mirr.im/1ENDujd http://t.co/Lqn12dKwny#4 BebeAjax Cape Town v Manchester United - Pre-season FriendlySir Alex Ferguson had never seen Bebe play a single game before sanctioning the move as he trusted the advice of his then assistant manager Carlos Queiroz. That proved to be a costly mistake.The forward arrived from Vitoria Guimaraes for around £8 million in 2010. Manchester United could have signed him on a free transfer but instead waited for him to join Vitoria before adding him to their squad during the same transfer window.Bebe had a torrid time at Manchester United and played just seven games during his four years at the club. During the time, the majority of his Manchester United career was spent on loan at clubs like Besiktas, Rio Ave and Pacos de Ferreira.B/R Football@brfootball10 years ago today, Sir Alex Ferguson broke his own rule by signing a player he'd never watched.Bebe went on to play just seven games in four years as a Manchester United player.5:41 AM · Aug 11, 2020593857310 years ago today, Sir Alex Ferguson broke his own rule by signing a player he'd never watched.Bebe went on to play just seven games in four years as a Manchester United player. https://t.co/cXczED2hOMHis disastrous outing with the Red Devils finally came to an end in 2014, when he was sold to Benfica for around £3 million.Bebe is now currently plying his trade in La Liga with Rayo Vallecano, having joined the club permanently in 2018.