Speaking to the Official Brighton Website, Albion manager Mark McGhee said: "It's a bitter blow, but I am absolutely party to the club's financial plight and under no allusions that we may have to accept an offer of this magnitude.
"I have been delighted with what Darren has done this season, and because of that Dick and I were already in negotiations to offer him a new contract and extend his existing deal for another two years. However, in light of Ipswich's bid, it was difficult for us to stand in his way.
"Darren wants the opportunity to play at the top end of the Championship, but we still did all that we could to try and keep him. Dick refused several offers from Ipswich, and I have tried to persuade him he should stay, but I couldn't win the argument.
"They are a team with a fabulous set up, a superb stadium and are at the top end of the division pushing for a place in the Premiership as opposed to our situation. People have to accept that, and we'll go on together."
Meanwhile Chairman Dick Knight explained that his side simply didn't take the first offer on the table: "I am extremely sorry, as all Albion fans will be, to see Darren leave the club.
"He's been a key player this season, which is why I turned down several Ipswich bids this week, but in our current financial situation the board were unanimous that we had no choice but to accept the sum Ipswich finally offered us.
"Mark McGhee didn't want to lose Darren either, but accepts that the club's financial position dictates it was an offer we couldn't refuse.
"Also, Darren is an ambitious player and was extremely excited by the prospect of joining a club very much involved in the race for the Premiership. On behalf of all at the Albion I would like to thank him for his contribution to our season, and wish him well for the future."