Declan Rice has submitted a written request to Fifa to transfer his registration from the Republic of Ireland to England, ending a long-running saga over his international allegiance.

The West Ham midfielder, whose consistently impressive displays this season have caught the eye, was born in Kingston-upon-Thames but his paternal grandparents are from Cork and he excelled for Ireland at junior level. The 20-year-old progressed to gain three senior caps, but all in friendly fixtures, permitting him to declare for the country of his birth.

Rice spent months deliberating before telephoning Mick McCarthy and Gareth Southgate on Wednesday to confirm he would seek to represent England in the Euro 2020 qualifiers. “This has been an extremely difficult decision and, in all honesty, not one I ever expected to be making at this stage of my career,” he said.

Rice said he had discussed the matter with family and friends as well as with McCarthy, Southgate and the former Ireland manager Martin O’Neill.

“Like so many people around the world, I consider myself to be of mixed nationality,” he added. “I am a proud Englishman, having been born and raised in London. However, I am just as proud of my family’s Irish heritage and my affinity and connection with the country. I have equal respect and love for both England and Ireland and therefore the national team I choose to represent is not a clear-cut, simple selection. Particularly not for a young lad who never dreamed of being in this position.

“Ultimately, it is a personal decision that I have made with my heart and my head, based on what I believe is best for my future. I fully accept that some Irish supporters will be disappointed by my decision, and that everyone has different opinions in regard to the rules around international representation. However, I hope that people can understand that I have made this decision with honesty, integrity and the full support of my family.”

His switch is a huge blow for McCarthy, who succeeded O’Neill in November, with the Ireland manager confirming he had fielded Rice’s call and accepted his decision. “Declan rang me today and said he has decided to give it a go with England,” he said. “Good luck to him.”

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Rice, who was at Chelsea’s academy before moving to West Ham in 2014, has been one of his club’s best players this season.

England begin their qualification campaign with games against the Czech Republic and Montenegro next month, with Rice’s availability for those fixtures dependent upon Fifa completing the paperwork around his registration.

“My pride at wearing the Irish shirt was always 100% genuine,” he added. “It was a great honour for myself and my family, and something I will always cherish. I would also like to make it clear that, in requesting to transfer my national team representation, I am not taking for granted a call-up to the England squad or making any assumptions about my future international career. However, out of respect for the Republic of Ireland, I felt it was right to announce this decision now and put an end to the speculation … In football, and in life, I have always tried to be completely honest and true to myself and my family at all times, and that is what I will continue to do.”