Declan Rice became Britain's most expensive player on Saturday as Arsenal signed the England midfielder from West Ham for a reported 105 million pounds ($137.5 million).Rice's blockbuster move surpassed the previous record 100 million fee paid by Manchester City for Jack Grealish in 2021 as Arsenal continue their spending spree in a bid to challenge for the Premier League title next season.The 24-year-old said in a letter to West Ham supporters that his desire to play at the "very highest level" lay behind his decision to join Arsenal.Rice's switch to the Emirates Stadium on a long-term contract comes just months after he lifted West Ham's first major trophy since 1980 in the Europa Conference League final against Fiorentina.Having moved across London, Rice will now be competing for the Champions League rather than Europe's third tier trophy."In football, amazing opportunities arise. Big clubs, like Arsenal, have come for me and it's really hard to turn down," Rice told Arsenal's website."You only ever get one career and I really believe in what Mikel (Arteta) is building here and the squad he's building.