Hammond leaves after seven years at the Withdean (Getty Images)

The 24-year-old central midfielder would have been available on a free transfer in the summer, having spent seven years with the Seagulls.

Boss Geraint Williams told the club website: "He enjoys the physical aspect of being a midfielder and has the energy to get from box to box.

"The fact that he has been captain at Brighton means he is a good character."

Seagulls chairman Dick Knight added: "We did everything possible to persuade Dean to stay, including offering him an extremely generous new contract with a get-out clause if we didn't get promotion this season.