Declan Rice has completed his £105m move from West Ham to Arsenal. The midfielder was Mikel Arteta’s top target and Arsenal have seen off competition from Manchester City to land the England international in a deal that makes him the most expensive British player.

Arsenal are paying a guaranteed £100m – matching the fee City paid for Jack Grealish two summers ago – plus £5m in add-ons. The arrival of Rice cleared the way for Granit Xhaka to join Bayer Leverkusen and makes it more likely that Thomas Partey, who has interest from Juventus and Saudi Arabian clubs, will depart.

Related: Arsenal confirm Jurriën Timber signing from Ajax in initial £34.3m deal

Rice is Arsenal’s third summer signing, after the forward Kai Havertz was bought from Chelsea for a fee rising to £65m and the defender Jurriën Timber came from Ajax in a deal that could reach €45m (£38.6m) with add-ons.

“With Mikel and how he works, the squad, how young everyone is, the energy around the club and also the challenge of getting Arsenal back to where they belong, that means a lot to me,” Rice said. “I know the fans really want that. For me as a player, I’ve come here really hungry to have more success and to spend my best years at this great club.”

The record fee paid by a British club is Chelsea’s £106.8m to Benfica for the Argentina midfielder Enzo Fernández in January.

In an emotional letter to West Ham fans, Rice said his goodbyes after “an absolute whirlwind of emotion” over the past few weeks. “I want you to know how tough a decision it has been for me to leave an environment that I have loved and cherished so much,” he said. “This club and its supporters will always be in my heart, and forever a part of who I am.

“Ultimately, though, it has only ever been about my ambition to play at the very highest level of the game. Playing on the opposite team to West Ham for the first time will be an unusual experience.

“I’m not sure yet exactly how I will feel, but I also know you will all understand and respect that my professional loyalties have to now lie with my new club.”

The West Ham joint-chairman David Sullivan revealed last month the club had a gentleman’s agreement with Rice to allow him to leave this summer after the 24-year-old turned down the offer of a highly lucrative new contract.

“I am sorry to see Declan leave us but I believe that everyone at West Ham United should be very proud of the part we have played in his journey from the Academy of Football at Chadwell Heath to becoming the most valuable young player in English football,” Sullivan said.

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“I would like to make it clear to our supporters that we did not want to sell Declan. We wanted to build our team around him and made a series of improved, long-term contract offers to secure his future.

“However, once Declan made it clear that he wished to move on and seek a new challenge, the club felt it would not be right to stand in his way, acting in the best interests of West Ham United.”