Freddie Ljungberg justified his transfer from Arsenal to West Ham United today with the claim that a great era for Arsene Wenger's side has finally reached its end.

The Sweden captain was unveiled by Eggert Magnusson, the West Ham chairman, as the club's fifth summer signing at a press conference this afternoon.

In comments that will confirm the worst fears among Arsenal fans that the club is in serious decline, the 30-year-old midfield player said Wenger had consistently failed to make the signings necessary to keep his team close to the top of European football.

Admitting that the departure of Thierry Henry for Barcelona last month was the final straw for him, Ljungberg said: "Two years ago when I signed my last contract [at Arsenal] we talked a lot about the future and about bringing great players to the club. Despite building the new stadium we wanted to stay top in England and do well in Europe. For me that didn't really happen.

"Other clubs came in for me last summer but I stayed because I wanted to stay loyal to Arsenal. But when Henry left this summer it felt like the end for me unfortunately. I felt like all the unbeaten players (from Arsenal's Premiership-winning 2003-04 side) had left but me. I wanted to be loyal but I felt like it was the right time."

Ljungberg joins Julien Faubert, Scott Parker, Craig Bellamy and Richard Wright as new arrivals at Upton Park. "When I spoke to the boss [Wenger] he wanted me to stay. There had to be something very, very special for me to leave.

"I'm coming here because I want to build a great team," Ljungberg said. "And why I want to join is because of Magnusson. He wants to bring them forward to be top of the country.

"He's willing to go to the transfer market to buy top players and mix them with players from the academy - West Ham have a great tradition for developing players through their academy. He wants to help take the club up and take them to the top in England. It's a big challenge for me."

Ljungberg joined Arsenal for £3 million from Swedish club Halmstads in 1998. He made 325 appearances and scored 72 goals and, until today, was the club's longest-serving player.