He was at one of Europe’s biggest clubs but George Dobson has no regrets about joining the team he has supported all his life.
The highly-rated central midfielder is a boyhood Hammers fan and jumped at the chance to sign for the club.
The 17-year-old arrives with a big reputation, having captained the Arsenal Under-18s last season.
He also made his breakthrough in the Arsenal under-21 team, playing alongside Jack Wilshere and Abou Diaby.
Dobson said he relised the chance to play for his hometown club and hoped to follow in the footsteps of fellow local boy Mark Noble by making an impression on the first team.
Dobson told the club’s official website: “I am over the moon to have signed and have been a West Ham fan since I was five – this is a surreal moment.
“Putting pen to paper is a dream come true for me. I had a great 10 years with Arsenal and they helped me as a footballer and as a person.
“But the time is right to move and I cannot wait to get started. I give 100% every time I put the shirt on and I will give everything for the team.
“With the amount of players who have come through the academy, it was a no-brainer for me.
“There are lots of opportunities here and you have just got to take them. I know I will have to work hard.
“Terry Westley is a great guy and has shown a lot of interest in me. That is really important for a young person and I am looking forward to working under him.”